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* I 

Frick Company" 

Sole Builders of 


Refrigerating and 
Ice Making Machinery" 

of tlx 

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New York— De La Vergne Machine Co. 
W. M. Schwenker 

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Norfolk. Ya.— Hunter Chemical Co. 
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Jackwnvlllc, Fla.- Jacknonville Rffr. Ice 

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Allcfbeay— United Storage Co. 
Detroit -Michiflran Ammonia Works. 
Chicago— Fuller A Fuller Co. 
A. Ma^DUS^SonsCo. 

St. Paal— Hauser A Sons Malting Co. 
Mllwaakce— Baumbacb-Reicbel Co. 
iatflaaapolia— Indianapolis Warehouse Co. 
Cievelao4— Cleveland Brewers Supplj Co. 
Cladoaatl— The Herman Goepper Co. 
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house Co. 
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Rees, Hawthorne and Dayton Streets, Chicago 
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PRA^n liM. 

COLi Nl 

'J H 












Author of "Ec,os in Cold Storage,** "Ice Cold Storage,*' etc. 




copyright, 1904, 1905 
By Nickbrson 8c Collins Co. 





147601 ^ . . ^ ^^ 

NOV 4 1910 H '0 7 ^ C' 4 


As a tribute ta his matchless enterprise 
and genius for practical and scientific 
research^ and in acknowledgment of 
valuable assistance rendered^ this work 
is affectionately inscribed. 

The Juthok,. 


The difficulties encountered in preparing a book on so broad 
a subject as practical cold storage' have been so great as at times 
to discourage the author from continuing. The author has en- 
deavored to collect the greater part of his own writings and at 
the same time has compiled from all available sources. The 
present book has the many shortcomings usually found in every 
pioneer work, and there are many gaps in the chain of informa- 
tion given for the reason that detailed knowledge has in many 
cases been lacking. A large portion of the general matter which 
has appeared on the subject of cold storage is of little or no value 
as a part of a book on this subject, for the reason that it con- 
tains many repetitions and contradictions, and for the most part 
has been written by persons not familiar with refrigeration either 
from a practical or scientific standpoint. The matter and in- 
formation which appeared prior to about 1895 is mostly value- 
less in the light of present information, as the earlier articles 
were generally incomplete and in part erroneous. 

Thop immense amount of labor involved in digging through 
the great piles of chaff to find the few grains of wheat has been 
out of all proportion to the actual results obtained. Reliable 
scientific data and the records of tests have in many cases been 
difficult or impossible to obtain. Very little along this line is 
in existence and some of it is jealously guarded by its pos- 
sessors. Practical information on the handling, packing and 
storing of perishable products is obtainable only in a small way 
for the reason that comparatively few operators of cold storage 
houses have made any record of results and can put their experi- 
ence in tangible form for the use of others. The author begs to 
acknowledge the assistance of his many friends among the en- 
gineers and cold storage men. It has been his aim to give due 
credit where any considerable amount of matter has been fur- 
nished by others. 


This book is intended to cover the field of appHed refrigera- 
tion with the exception of ice making, ice machines, and the 
technical and theoretical side of the mechanical production of 
refrigeration. These important matters are fully treated by sev- 
eral valuable and comprehensive works. The reader is referred 
to these books for the data, theory and information necessary to 
a full understanding of the principles of thermo-dynamics and 
refrigerating machine construction and operation. 

There is much regarding the use of ice, both natural and 
artificial, as a practical refrigerant, even on a large scale, which 
has not heretofore been fully described. The possibilities of 
successful refrigeration by means of ice have not been carefully 
studied and given due consideration. If rightly applied ice either 
natural or manufactured, in combination with salt, will produce 
any results in the preservation of perishable products, which 
may be produced by any means of cooling; limited of course, 
by the range of temperature which can be obtained. The im- 
portance and extent of this branch of the refrigerating industry 
has not been appreciated by those who have given their time to 
the study of refrigeration. The development of the mechanical 
systems of refrigeration came at a time when the use of ice as 
a refrigerant had not been reduced to a scientific basis, conse- 
quently our best talent was directed toward the perfecting and 
introducing of the ice machine. Nevertheless, there are many 
successful ice cold storage houses who are doing fully as per- 
fect work as the best machine refrigerated houses. This is not 
to the discredit of the machine cooled houses in the least, and 
it is generally admitted that the average ice cold storage turns 
out goods greatly inferior to the average machine cold storage. 
At the same time the value of products which are daily refrig- 
erated by ice for preservation, exceeds by far those refrigerated 
by mechanical means. This statement is best appreciated when 
we consider that a large part of the output of the hundreds of 
ice factories? is used in small refrigerators for the temporary safe 
keeping of fruit, vegetables, meats, dairy products, etc. ; that the 
immense natural ice crop annually harvested is consumed in the 
same way ; that an important portion of the eggs, butter, cheese, 
fruit, etc., are stored in warehouses cooled by ice, or ice and 
salt, and that perishable* goods during transportation are kept 


cool by ice almost exclusively. From these facts it is evident that 
a description of the manner of securing and storing the natural 
ice crop and the best methods of utilizing ice, either natural or 
artificial, for cooling or freezing purposes, must be of consider- 
able value to the users of refrigeration generally. 

An important branch of cold storage design, and in fact 
all work in refrigeration, is the design and construction of walls 
which form insulation against heat, and built of such materials 
as may be had at a moderate cost. The chapter on insulation has 
aimed to give the results of the best information at present ob- 
tainable on diis subject, both in the United States and in foreign 

The chapters on the practical operating of cold storage houses 
and the care and handling of goods for storage have been writ- 
ten largely from, the autlior's practical experience, supplemented 
by information obtained from others. So many different kinds 
of goods are now placed in cold storage for preservation, that 
the experience of many persons must necessarily have been added 
together to aggregate the results given ; even then the information 
is not as complete as it might be. General directions are given for 
the handling of a cold storage house without reference to any 
particular product, and if these are followed understandingly 
and care and judgment used, the cold storage manager may avoid 
many of the errors common to those new to the business. It 
must be remembered that a good house poorly handled cannot 
compete with an inferior house well handled. At least one-half 
is in the management and too much care cannot be exercised in 
looking after the details of a refrigerating installation, not only 
for the purpose of securing economy in operation of same, but 
alsL» to insure the keeping of the stored goods in the best condi- 

By far the major portion of what is printed in this book is 
from the original writings of the author ; a portion of which has 
appeared in the columns of Ice and Refrigeration ; The Ice Trade 
lournal, etc., as articles under the titles of " Eggs in Cold Stor- 
age," " Ice Cold Storage," etc. It was because of the success 
of the articles on " Eggs in Cold Storage," which were subse- 
quently printed in pamphlet form, and the complimentary recep- 
tion of same, which encouraged the author to undertake the pres- 


ent work. It is now submitted to the trade with a full appre- 
ciation of its imperfections and incompleteness. As far as pos- 
sible these will be remedied in future editions. It is the earnest 
request of the author that those who find errors or omissions or 
can suggest in any way improvements, correspond with the au- 
thor to the end that " Practical Cold Storage " may be made as 
complete and accurate as possible. 

Any information which will further the interests of the busi- 
ness, will in turn benefit all who are engaged therein. For any 
one to believe that he is the possessor of secret information 
which is vital to his success over competitors, is in a great ma- 
jority of cases the extreme of absurdity. Much of the matter 
appearing in this publication has at some time been considered 
as trade secrets. The false and narrow-minded position taken 
by some in connection with this matter is well illustrated by cer- 
tain remarks made to the writer in regard to the publication of 
this book. The following is a sample : " Now that you have 
this information accumulated, why not keep it for your own 
use instead of giving it away ? " It is quite true that the author 
has expended in time, effort and money in connection with the 
preparation of the matter contained in this book, much more 
than he can be remunerated for in its sale. It is, however, here 
given for what it is worth and with the earnest wish that it 
may be of substantial benefit to many readers. 

It might not be out of place to call the reader's attention 
to the fact that, in practically all the original matter by the 
author contained in this book, reasons are given for statements 
made so far as practicable. This enables the new beginner or 
student to study intelligently the natural laws which govern the 
principles of refrigeration. Comment and criticism has been 
freely bestowed without fear or favor on the various ideas, sys- 
tems and methods which do not meet the approval of the author. 
Matter which has been compiled or extracted from other sources 
has in some cases been changed or modified to suit the individual 
ideas of the author. Should the advocates of anything here criti- 
cised feel that they have not had a fair presentation the author 
will be glad to take the matter up and discuss the points involved. 

While this work is in some respects imperfect and there is 
no doubt room for the addition of much information, reliable data. 


and the results of extended observations and tests, there has not 
heretofore been anything like as complete a presentation of the 
entire subject ; and in consideration of this fact the reader is 
requested not to be too critical. If any errors or lack of details 
are noted, the author would be pleased to acknowledge same and 
will endeavor to explain the points at fault. No other object 
has been in mind in preparing this book than a furtherance of 
scientific knowledge on the subject of refrigeration as applied 
to the preservation of perishable products, and the great assis- 
tance rendered by those who have assisted is hereby acknowl- 
edged. The combination and comparison of information is bene- 
ficial, and if those who have further data or records of tests 
will only put them before others in their line of business, no 
loss will be sustained by the individual giving the information, 
while much general good will result. 


There is no authentic history of the use of refrigeration as 
applied to what is now popularly called *' cold storage," and it 
is only within the past twenty-five or thirty years that the prac- 
tical usefulness of refrigerated storage has been appreciated by 
the world at large; In the year 1626 Lord Bacon is said to have 
taken a chill from the stuffing of a chicken with snow, in order 
to preserve it, which resulted in his death. It would seem that 
the death of so eminent a person from such a cause should have 
attracted attention to the possibilities of applied refrigeration, 
but either the poor success of the experiment, or the fatal result 
to its originator seems to have had a deterrent eflFect on fur- 
ther investigation along this line at that period. 

It is doubtful whether any scientific demonstration or com- 
mercial enterprise of recent years has been of greater moment 
to the human race than the science of refrigeration and its prac- 
tical application in the modern cold storage industry. When 
scientific inquiry had proven the efficacy of low temperatures in 
preventing decay and had demonstrated the possibility of obtain- 
ing and maintaining low temperatures at will, the cold storage 
business of today was but the natural evolution resulting from 
such demonstration. When it became apparent that profit was 
obtainable by placing perishable goods in cold storage during a 
period of glut or surplus and disposing of them at some sub- 
sequent period of comparative scarcity or increased demand, the 
building of cold storage houses and the perfection of machinery or 
apparatus for their economical operation became the inevitable 
result. The pioneers in the cold storage business were specula- 
tors of the extreme kind, but this cannot be said of those in 
the business today. Where in the early days the cold storage 
operator owned the goods he stored almost entirely, and his 
customers were uncertain, now the goods placed in cold storage 


are almost wholly owned by dealers, and are held for the sup- 
plying of their trade. 

Refrigeration has four chief uses in the economy of nature 
and in commerce : 

I. — To prevent premature decay of perishable products. 

2. — To lengthen the period ot consumption and thus greatly in- 
crease production. 

3. — To enable the owner to market his products at will. 

4. — To make possible transportation in good condition from point 
of production to point of consumption, irrespective of distance. 

First : Without refrigeration there would he much actual 
waste from decomposition before it would be possible to place 
perishable food products in the possession of the consumers. 
The immense fruit trade of the Pacific coast would never have 
bec*n developed without the assistance of refrigeration, nor could 
the surplus meat products of the southern hemisphere have been 
brought half way around the globe to relieve the shortage in 
thickly settled England without its aid. Without the aid of 
refrigeration to create a constant market, the production of 
meats, of eggs, of fruits and other food products would be 
greatly curtailed. 

Second : In many classes of produce the ordinary season of 
consumption was formerly limited to the immediate period of 
production, or but briefly beyond. Now nearly all fruits may be 
purchased at any season of the year and dairy and other products 
are for sale in good condition and at reasonable prices the year 

Third: Instead of being obliged to sell perishable goods, 
when produced or purchased, at any price obtainable, the owner 
can now put away in cold storage a portion or all of his products 
to await a suitable time for selling. This not only results in a 
better average price to the producer, but places perishable food 
stuflfs at the command of the consumer at a reasonable price at 
all times and greatly extends the period of profitable trading in 
such products. 

Fourth : The certainty and perfection with which food 
products may be conveyed from the place of production to the 
large centers of population where they are to be consumed is 
one of the triumphs of refrigeration ; yet the refrigerator car 
service is only in its infancy so far as perfection of results is 


concerned. It is safe to say that our immense Pacific coast fruit 
trade could not exist without it. The over sea carriage of prod- 
ucts has also been developed along with the development of 
refrigeration as applied to this work. 

Cold storage is a benefit to all mankind in that it allows of 
a greater variety of food during all seasons of the year. Health 
and longevity are promoted by the free consumption of fruits, 
and the placing of fresh fruits at the disposal of even the poor- 
est of our citizens during every month in the year will certainly 
result in a wholesale benefit to mankind, so far-reaching in its 
effects as to be incalculable. 

Physicians and scientists who have investigated the subject 
unite in praising the modern practice of refrigeration as applied 
to the preservation of food products and in arresting decay in 
all articles of value liable to injury by exposure to high or nor- 
mal temperatures. A prominent English physician* in an address 
before the Sanitary Institute at their Congress at Birmingham 
in 1898, after describing at length the various methods, namely : 
Drying, smoking, salting, sugar and vinegar, exclusion of air 
(canning), antiseptics, chemicals, etc., "in use as food preserva- 
tives, has this to say of refrigeration : 

This brings us then to the last of the modern methods of food pres- 
ervation on the large as well as on the small scale, and as it is the last, 
so it is the best. The fishmonger avails himself of it in his ice well and 
on his stall. It is by its agency that all the perishable food on our great 
liners is preserved during even prolonged voyages, and it is used in 
the great food depots of many of our large towns. In this town tons of 
perishable foods are continually preserved by its action, and where such 
stores do not exist they ought to be provided. In this way all perishable 
articles can be kept until such times as they shall be required for sale 
and distribution. 

Formerly the methods of producing cold were complicated and dear, 
and had many drawbacks, but these have been overcome. * * * Cold 
acts not by killing the organisms that effect decomposition, but only by 
inhibiting their action; in which respect it differs from heat and certain 
chemical antiseptics, such as chlorine, for instance. 

Among the advantages of preser\'ation by refrigeration may be men- 
tioned : — 

I — It has been proved the most effective as a preservative, surpassing 
in efficiency, salting, boric compounds, or any other practical method. 

2 — It adds nothing and subtracts nothing from the article preserved, 
not even the water, and in no material sense alters its quality. 

3 — It causes no change of appearance or taste, but leaves the meat 
or other substance substantially in its original condition, while it renders 
it neither less nutritious nor less digestible, which cannot be said of 
some other methods in common use. 

♦Alfred Hill, M. D., F. R. S.. Edin. F I. C. Medical Officer of Healtli and Public Ana- 
lyst to the City of Birmingham, Eng. 


My contention is that all additions to food whose influence on health 
is doubtful ought to be prohibited and their use supplemented by refri- 

Strong language like this coming from such an eminent 
authority not only vouches for the usefulness of refrigeration, 
but also for the perfection of its results, and to a thinking per- 
son offers an assurance that an industry established on so broad 
a basis must present an ever widening field of usefulness. New 
products are constantly being added to those which are placed in 
cold storage for safe keeping or preservation, and it seems not 
a wild prediction to say that at some time in the future the great 
majority of our food products and other perishable goods will be 
handled in and sold from refrigerated rooms. 

Considering the importance the cold storage industry has 
already attained, its rapid growth and future outlook, the amount 
of accurate information available to those engaged in the busi- 
ness seems very meager. The difficulties to be overcome, the 
skill required, and the importance of a well designed structure 
are not usually explained by those interested in promoting new 
enterprises in this line, and consequently not appreciated by those 
making the investment. Financial disaster has overtaken many 
large companies who have erected costly refrigerating ware- 
houses; those which have succeeded have in many cases been 
forced to install new systems, make expensive changes, and 
make a thorough study of the products handled. The experi- 
ence of nearly all has been emphasized at times by heavy losses 
paid in claims made by customers for damage to goods while in 
storage, or the necessity of running a large house while doing 
a very small business. Those about to become interested in 
business may find food for thought in the above, and the his- 
tory of a dozen houses, in different localities, will furnish valu- 
able information for would-be investors. 

The scarcity of knowledge on the subject in hand, while 
being partly the result of the partially developed state of the 
art until very recently, is also very largely owing to narrow- 
mindedness on the part of some of the older members of the 
craft who have largely obtained their skill by years of experience 
and study, some of them having expended large sums on experi- 
mental work. The same experiments have perhaps been made 
before, and are of necessity to be made again by others, simply 


because the first experimenter would not give other people the 
benefit of his experience. It seems that at the present stage 
in the development of refrigeration the improvements to be 
made during the next twenty-five years will be of very much less 
importance than those made during the last twenty-five years; 
trade secrets, so jealously guarded by some, must disappear, as 
they have in other branches of engineering. Storage men have 
been obliged to work out their own salvation in solving problems, 
sometimes, how^ever, sending their most difficult points to be an- 
swered through the columns of the trade journals, and, perhaps, 
comparing ideas with those of their personal friends in the same 
line of business. It is to be observed that the most progressive 
and up-to-date manufacturing concerns in the United States are 
today giving their contemporaries every opportunity to observe 
their methods, and are very willing and anxious to talk over mat- 
ters pertaining to their work from an unselfish standpoint. So, 
too, the successful cold storage of the future will be sure to make 
" visitors welcome." 

In anything which appears in this book, it is not the author's 
intention to convey the idea that any mere theoretical knowledge 
which can be acquired by reading and study, or even by an ex- 
change of ideas in conversation, can take the place of practical 
observation in actual house management; but there are applica- 
tions of well known laws which are not generally understood by 
storage men and their progress is handicapped from lack of this 
theoretical knowledge. The two following illustrations, bearing 
on temperature and ventilation, are among the common errors 
made in practice, yet easily understood when studied and tested : 
Some storage houses formerly held their egg rooms at 33° F., 
fearing any nearer approach to the freezing point of water (32° 
F.), thinking the eggs would freeze. A simple experiment would 
settle this point, giving the exact freezing temperature, as well 
as the effect of any low temperature on the egg tissues. Eggs 
will not freeze at 28"* F. Again, others have thought to venti- 
late by opening doors during warm weather. It never happens 
that storage rooms can be benefited by this treatment at any 
time during the summer months, and only occasionally during 
the spring and fall. The dew point of outside air is rarely below 
45" F. during summer, and when cooled to the temperature of 


an egg room, moisture will be deposited on the goods in stor- 
age, causing a vigorous growth of mildew. 

The question of the proper temperature at which to carry 
goods is of the first importance. Correct temperatures alone, 
however, will not produce successful results, any more than a 
good air circulation or correct ventilation would give good 
results with a wrong temperature. The common impression of 
cold storage is what the name implies — simply a building in 
which the rooms may be cooled to a low degree as compared 
with the outside air. Even those w^ho manufacture and install 
refrigerating machinery and apparatus often show either gross 
carelessness or ignorance of the requirements of a house which 
will produce successful results. After a careful examination of 
some of the recently constructed houses supposed to be strictly 
modern and up-to-date, the writer got the impression that the 
designers regarded temperature as the only requisite for perfect 
work. Some of the rooms in these new houses are simply insul- 
ated and fitted with brine or ammonia pipes, the proper loca- 
tion of same having received no attention whatever, being placed, 
in most cases, in convenient proximity to the pipe main, and in 
one or two instances, the top pipe of the cooling coils was fully 
two feet from the ceiling. The necessity for providing for air 
circulation seemed not worthy of consideration, to say nothing 
of the lack of anything like an efficient ventilating system. These 
things are mentioned here for the purpose of cautioning against 
a superficial study of cold storage problems. It is advisable for 
everyone interested to understand the underlying laws which 
govern the results to be obtained. Read carefully the chapters 
on "Air Circulation," •'Humidity" and "Ventilation." 

Cold storage, if the right system is installed and properly 
handled, will produce some remarkable results in the preserva- 
tion of perishable products. It must not be expected, however, 
that the quality and condition of the goods are improved by 
storage. Cold storage does not insure against natural deteriora- 
tion. Goods for cold storage must be in prime condition and 
selected by an experienced person if it is expected to carry them 
to the limit of their possible life. A cold storage house suc- 
cessfully operated and managed will supply a uniform tempera- 
ture at the proper degree throughout the storage season. It 


will regulate tlie humidity at the proper point and will supply 
fresh air properly treated to force out the accumulated gases. 
The storing of unsuitable, imperfect and inferior goods has led to 
much misunderstanding and some litigation between the man 
who stores the goods and the warehouse man. Both should, if 
possible, be familiar with the condition of the goods they are 
handling; the different stages of ripeness, quality and liability 
to deterioration. Cold storage cannot improve the physical con- 
dition of perishable goods and is in no way responsible for 
damage or decay which may arise from improper picking, grad- 
ing, packing or handling before placing in the storage house. If 
these things are properly understood by all concerned much mis- 
understanding will be avoided, and greater satisfaction and profit 
will result to all concerned. 



Mother earth as a source of available refrigeration, is with- 
out doubt a pioneer. In the temperate zone at a depth of a 
few feet below the surface, a fairly uniform temperature is to 
be obtained at all seasons of about 50° to 60° F. In some cases 
a much lower temperature is obtained. The same principle is 
true in any climate, the earth acting as an equalizer between ex- 
tremes of temperature, if such exist. Caves in the rock, of nat- 
ural formation, are in existence, in which ice remains the year 
around, and many caves are used for the keeping of perishable 
goods. The Ruskin Co-operative Colony, located at Ruskin, 
Tennessee, has a fine large cave on its property which is utilized 
as a cold storage warehouse. The even temperature, dryness and 
purity of the atmosphere to be met with in some caves are quite 
remarkable, owing no doubt to the absorptive and purifying 
qualities of the rock and earth, as well as to the low temperature 


Cellars are practically caves built by the hand of man, and 
if well and properly built are ecjually good for the purpose of 
retarding decomposition in perishable goods. A journey through 
the Western states reveals many farmers who are the possessors 
of **root-ccllars," considered the first necessity of successful 
farming, the new settler building his cellar at the same time as 
his log house. A root-cellar is used partly as a protection against 
frost, but it also enables the owner to keep his vegetables in fair 
condition during the warm weather of the spring and summer 
months. The use of cellars for long keeping of dairy products 
is familiar to all. Many of us can recollect how our mothers put 



down butter in June and kept it until the next winter, and per- 
haps it will be claimed by some, that the butter was as good in 
January as when it was put down. It was not as good, far from 
it. If you think it was, try the experiment to-day and you will 
see how it will taste and how much it will sell for in January in 
competition with the same butter stored in a modern freezer. 
The butter made years ago was no better either. No better but- 
ter was ever made than we are producing to-day. In short, cel- 
lars were considered good because they had no competition — 
they were the best before the advent of improved means of cool- 
ing. Cellars are still of value for the temporary safe keeping of 
goods from day to day, or for the storage of goods requiring 
only a comparatively high temperature, but with a good refrig- 
erator in the house, the chief duty of a cellar, nowadays, is to 
contain the furnace, and as a storage for coal and other non- 
perishable household necessities. 


The use of ice as a refrigerant during the summer months 
is a comparatively modern innovation, and not until the nine- 
teenth century did the ice trade reach anything like systematic 
development. The possibility of securing a quantity of ice dur- 
ing cold weather and keeping it for use during the heated term 
seems not to have occurred to the people of revolutionary times. 
About 1805 the first large ice house for the storage of natural 
ice was built, and with a constantly increasing growth, the 
business rose to immense proportions in i860 to 1870. The 
amount harvested is now much larger than at that time and con- 
stantly increasing, but the business is now divided between nat- 
ural ice and that made by mechanical means. 

The first attempt at utilizing ice for cold storage purposes 
was either by placing the goods to be preserved directly on the 
ice or by packing ice around the goods. These methods are in 
use at present as for instance in the shipping of poultry, fish and 
oysters, and the placing of fruit and vegetables on ice for pres- 
ervation and to improve their palatability. The first form of re- 
frigerator proper consisted merely of a box with ice in one end 
and the perishable goods in the other. This form of cooler is 
illustrated in the old style ice chests, which are now mostly su- 



perseded by the better form of house refrigerator with ice at the 
top and storage space below. On a larger scale small rooms were 
built within and surrounded by the ice in an ice house. These 
rooms were of poor design and did not do good work, largely the 
result of no circulation of air within the room. The principle of 
air circulation was recognized later, and by placing the ice over 
the space to be cooled, a long step in the right direction was 
taken. By this method the air was induced to circulate over the 
ice and down into the storage room. During warm weather the 
circulation of air in contact with the ice purified the air and 
produced a more uniformly low temperature. Many houses on 
this system are still in existence, although rapidly being super- 
seded by improved forms. 

About the time when the overhead ice cold storage houses 
were being installed freely, mechanical refrigeration came into 
the field. Mechanical refrigeration in which the storage rooms 
are cooled by frozen surfaces, usually in the form of brine or 
ammonia pipes, was much superior to ice refrigeration, in that 
the temperature could be controlled more readily and held at 
any point desired and that a drier atmosphere was produced. 
Ice and mechanical refrigeration will be discussed fully in treat- 
ing of construction and in discussing the value of different sys- 
tems for different purposes. It may be remarked in passing that 
ice is at present and will probably always remain a very useful 
and correct medium of refrigeration, especially for the smaller 
rooms and some purposes. 


The first method of mechanical refrigeration to come into 
general use, and one which is still largely in use on ocean going 
steam vessels, was by means of the compressed air machines. 
These operate by compressing atmospheric air to a high tension, 
cooling it, and expanding it down to atmospheric pressure di- 
rectly into the chamber to be cooled. These machines are very 
uneconomical in that the compressed gas is not liquefied. Pres- 
ent practice in compression machines mostly employs either am- 
monia gas or carbon dioxide gas, both of which may be liquefied 
by pressures and temperatures readily obtainable. Other gases 
are in use also, but ammonia is the favorite as it liquefies more 


easily. The apparatus known as the absorption ammonia sys- 
tem is really a chemical rather than a mechanical process, but 
is usually classed along with the mechanical systems. In this 
system, the ammonia gas is driven off from aqua ammonia under 
pressure, by heating; the gas is liquefied by cooling, and the re- 
frigerating effect obtained by expanding the liquid ammonia 
thus obtained through pipes surrounded by the medium to be 
cooled. This system is quite largely in use and preferred by 
many to the compression system, although the latter is most 
largely in use. In the so-called vacuum machines water is used 
as the refrigerating medium, its vaporization at low temperatures 
being effected by producing a vacuum by means of pumps, the 
vacuum being assisted by sulphuric acid. This system is very 
little used. 

The history of the development of cold storage up to the 
present shows that much time, money and skill has been expended 
in perfecting machinery and apparatus for the production of 
refrigeration. Comparatively little attention has been given to 
the application of the cold produced, through scientific systems, 
to the preservation of perishable products. It was deemed suf- 
ficient that temperature should be fully under control, and the 
providing of means for regulating humidity, air circulation, ven- 
tilation, etc., has been overlooked. It is one of the purposes of 
this book to fully explain the practical application of refrigera- 
tion to cold storage purposes, irrespective of how the refrigeration 
is primarily produced. The best means of creating refrigeration 
are necessarily determined by purely local conditions, while prin- 
ciples of application remain always the same. 






As a means of preserving perishable food products, and in 
some cases other goods, from decay or deterioration, refrigera- 
tion has come into use with a rapidity that has surprised its most 
sanguine advocates. The author has been identified with the 
produce and refrigerating industries for more than twenty years, 
and during the last half of this period has feared that the cold 
storage business was likely to be overdone. At present there 
seems no immediate prospect of such a condition, and it is prob- 
able that some years will elapse before there will be more cold 
storage space than goods to fill it. This seems the more probable 
when we consider the diversified products which are now stored 
in refrigerated rooms for preservation. Furs, as an illustration, 
are now placed in cold storage to prevent damage from moths, 
and to preserve the texture of the skins, and the best furriers 
report the results as greatly superior to the old method of treat- 
ment. Not only are the ravages of the moths prevented, but the 
furs come out of cold storage actually improved in appearance. 
Dried fruits are now perfectly kept during the w^arm months by 
placing in cold storage. Xuts are kept in the best possible con- 
dition by storing in cold rooms. Potatoes and cabbage are carried 
through the winter and turned out in a condition not thought pos- 
sible years ago. These are only a few of the products compara- 
tively new to cold storage. Each year finds something new in 
cold storage for safe keeping, and new uses are being found for 
refrigeration continually. There seems no limit to the possibili- 
ties of the business. It is certainly only a matter of time when 
the bulk of perishable products will be handled in and sold from 
cold storage. 

The starting and building up of a cold storage business re- 
quires all the business sagacity and ability usually necessary to 


success in any other line, and in addition there are some special 
qualifications which it may be worth while to consider. The 
formation of a company, the selection of a system of refrigera- 
tion, and the proper construction of the cold storage building are 
merely preliminary to the actual hard work and care necessary 
to success, and the cold storage business may develop into more 
of an undertaking than the average person has any idea of. Even 
after some investigation the points are not always as plain as 
they should be. After the house is built business must be ob- 
tained, and satisfactory results given to customers or the ven- 
ture will prove a failure. 

There are many cold storage men now operating houses who 
complain of poor business, and think there is no demand for cold 
storage in their locality, when the simple truth is that they have 
not the proper facilities for the preservation of the goods they 
try to handle. They turn out musty eggs, strong butter and 
rotten apples, and consequently their customers only place in 
storage what they are compelled to. Cases may be cited where 
a properly-equipped house has been started in competition with 
the kind above described, and obtained a profitable business from 
the start. In progressive times like the present, when competi- 
tion is sharp, it is poor business policy, if not positively suicidal, 
to go into business with anything except the best facilities. If 
you are going into the cold storage business, build a good house, 
and equip it with modern apparatus from designs by a practical 
man. A cheap house should not be considered. 

An enterprising and self-reliant man is usually at the head 
of a new cold storage enterprise. It requires both these qualifi- 
cations to establish a house where apparently little demand exists 
for such a concern, and generally this is about the situation where 
there is no cold storage house. There cannot, of course, be busi- 
ness done in the cold storage line where no cold storage house 
exists ; but an intelligent canvass of the situation should indicate 
the probability or not of business following the erection of a 
house. If the situation shows fair prospects there can be no 
failure if the enterprise is handled with the same care and ability 
necessary for success in other lines of business. Cold storage 
houses have been constructed with small apparent demand for 
the space, but after being in business for a year or two to prove 


an ability to carry goods well, the house has done a good busi- 
ness. In not a single instance known to the author has a well- 
built, properly-equipped and carefully-handled cold storage house 
been a source of loss to its owners. In determining the advisa- 
bility of erecting a house, it is well to have enough business as- 
sured, if possible, to pay operating expenses. If this much can 
be had the first season, the success of the business is no longer in 
doubt, and the house will generally pay nicely the second or third 
year. Should the owners be in the produce business, and buy 
and store enough goods to pay the operating expenses, they can 
demonstrate the success of the house the first year or two on their 
own account, and in future seasons obtain outside business very 
easily. Of course many houses are run for private use only, and 
the remarks above do not apply to such cases. It is true that 
there have been a good many failures in the cold storage business, 
but they are invariably the result of a poor house or poor han- 
dling, with the resulting heavy claims for damage to goods in 
storage, or over-capitalization and mismanagement. 

Very little reliable information can be obtained by those 
who contemplate the erection of a cold storage house from people 
already in the business; especially if in the immediate vicinity 
of the proposed house. This is because those in the business al- 
ready, regard the building of a new plant as more or less direct 
competition, and are quite liable to be biased in their views of 
the cold storage business in general, and of the proposed plant in 
particular. There is one thing which may be put down as un- 
necessary, that is the putting up of a small, cheap house as a 
trial, expecting, if it pays, to put up a larger and a better one. 
A small, cheap house, while not certain to be a failure, is more 
than likely to be so, and consequently the larger and better house 
is never built, and another is added to the ranks of those who 
think cold storage of no value, and a failure in a business way. 
Build well, if at all — it is not necessary to experiment, as this 
has been done repeatedly already, and the results from a well- 
built cold storage house are to be depended upon. The popula- 
tion of a town or city does not always indicate its ability to sup- 
port a cold storage warehouse. A large residence population 
has very little need for such an establishment, while a compara- 
tively small wholesale center at once makes a demand for stor- 


age for perishable goods. A large town, located in a rich pro- 
ducing district, generally gives a good opening for the upbuild- 
ing of a business, particularly where the chief articles of pro- 
duction are eggs, butter, cheese or fruits. 


The cost of a fully-equipped cold storage building is some- 
thing startling to many who contemplate embarking in the busi- 
ness. It is sometimes two or three times as much as was thought 
possible — many persons having an idea seemingly that a cold 
storage house can be put up for about the same cost as an ordi- 
nary structure. The shell of a cold storage house is only a por- 
tion of the total cost, and never exceeds half the cost. In many 
cases it is only one-third the cost of the finished building. 
This varies with the character of the structure, class of in- 
sulation, and type of refrigerating equipment. It may be 
stated as positive that there is no such thing as a 
cheap cold storage house which will at the same time do 
good work. Because of the cost of internal arrangements and 
equipment, a cold storage cannot be compared wath any other 
kind of a building, and the reason why people are surprised at the 
cost is because they make comparisons with buildings of ordi- 
nary construction. Probably two out of three persons who in- 
vestigate with the idea of building are deterred because of the 
expense running higher than anticipated. The reader who has 
preconceived ideas on the cost of a properly-equipped plant, 
may safely prepare for a shock should he wish to obtain estimates. 

The cost of a well-insulated and carefully-equipped house 
cannot be stated accurately without knowing the cost of ma- 
terials and labor at the building site, and the exact plan and de- 
tails of construction, but a few suggestions are made here as a 
guide to those interested. A good frame building, well insu- 
lated and equipped with machinery under the "Cooper System." 
as illustrated in the chapter on "Refrigeration from Ice,'' and in- 
cluding the cost of a cheaply-constructed ice room built adjoin- 
ing the storage house, will be, for a house of twenty carloads 
capacity, between $7,000 and $10,000. This cost does not in- 
clude the value of a building site, which necessarily would be 
much greater irl some localities than in others. In case an ice 


dealer, with no ice house to build, and perhaps some available 
power for ice-crushing and elevating, should undertake the busi- 
ness, the cost might be cut down probably $500 to $1,000. A 
smaller house, of ten or twelve cars capacity, could be built for 
about $5,000 to $7,000. The cost is more in proportion as the 
capacity grows less. A larger house, of say eighty carloads ca- 
pacity, could be built and equipped for about $20,000 to $30,000, 
including ice house. A small room holding from one to three 
cars may be built for $800 to $2,000 complete. A wide range is 
given in these estimates for the reason that it is necessary owing 
to widely varying costs in different parts of the country. Prod- 
ucts stored and number of rooms a house is divided into also in- 
fluence costs materially. The figures here given are approxi- 
mate costs of cold storage rooms or buildings equipped with the 
Cooper system, but this cost is not much more than a well-built 
house with the overhead ice systems, described in the chapter on 
''Refrigeration from Ice." The mechanical or ammonia system 
costs much more, for the smaller size of houses or rooms, as the 
capacity is increased the costs approach each other more nearly, 
but everything else being equal the Cooper system may be in- 
stalled in a house of any size for less than an ammonia system 
with brine circulation. Direct expansion may be installed for 
less, but direct expansion is not to be considered for first class 
cold storage work. 

The question is often asked as to the size of house to be 
built in a given locality. The author always withholds an answer 
until he is personally acquainted with all the conditions which 
can possibly be known. Only in exceptional cases are houses of 
a smaller capacity than twenty carloads recommended, for the 
reason that the cost of building and operating is so much more in 
proportion. For private use there is no limit to size, and rooms 
of as small capacity as one or two cars have been designed, giving 
good service and satisfaction to their owners. These small rooms 
are intended for temporary holding, but very successful results 
are obtained for long-period holding, when the rooms are 
equipped with the brine system. 


The product which may be depended upon to furnish the 
largest portion of the business to a newly-established cold storage 


depends on the location. Some houses are built solely for cheese, 
others for eggs, and others only for apples ; but generally speak- 
^"&» ^ggs form the largest and best paying product which is han- 
dled in cold storage. Eggs are probably the most difficult of all 
products to successfully carry for a period of six or eight 
months. If they are stored in a too dry atmosphere they dry out 
or shrink, and in this condition decay more quickly. If the air 
is too moist the eggs will mold and become musty. There is 
more danger of having a room too moist than too dry, and the 
damage resulting from too moist a room is also much greater. 
The best temperature for eggs is 29° to 30° F., and they are car- 
ried at this temperature by the best houses. A forced circulation 
of air is beneficial, and the moisture in the air should be regulated 
to the proper degree. For testing the air moisture of a cold stor- 
age room an instrument called the sling psychrometer is used. 
The subject of humidity is rather complicated, and the reader is 
referred to chapter on "Humidity," and "Eggs in Cold Storage," 
for a more comprehensive treatment of this subject. 

Butter is probably second in importance to eggs, and all 
cold storage houses have rooms fitted up especially for this prod- 
uct. The correct temperature for carrying butter has not been 
definitely settled by a majority agreeing on some one tempera- 
ture, and at present butter is held in cold storage at tempera- 
tures ranging from below zero to 25° F. The most common tem- 
perature now is between 12° and 15° F., and the author believes 
this to be low enough. Many practical men insist that zero is 
better, and some houses are carrying it at this temperature. Still 
others are holding temperatures for butter at from zero to 10** F. 
There seems a decided movement toward zero and below and we 
may all have to accept this at some future time. A butter stor- 
age room should only be kept dry enough to prevent the forma- 
tion of mold, and generally no attention is paid to the matter of 
humidity ; the room being amply dry, nothing further is thought 
of it. If butter rooms are too dry, as they frequently are, it 
leads to a bad drying out of the packages, and the surface of the 
butter as well, causing it to get "air-struck" or "strong" and 
shrink in weight. Butter, in order to keep well in cold storage, 
must be protected from contact with the air. Much has been said 
about freezing butter, but the butter fat practically has no freez- 


ing point, and it simply gets harder and harder the lower the 
temperature; so the idea that butter freezes at a temperature just 
under 32° F. is entirely erroneous. (See chapter on " Butter in 
Cold Storage " for more complete information.) 

Cheese is not ordinarily considered so difficult a product as 
butter and eggs to successfully refrigerate, but this idea comes 
largely from the fact that cheese has only recently been well han- 
dled in cold storage, and the possibilities of refrigeration for this 
purpose have not been demonstrated fully. Cheese will not 
spoil if stored in cellars or basements; nevertheless a properly- 
equipped cold storage room will quickly pay for itself in the im- 
proved results obtainable. Cheese should be carried at about the 
same degree of humidity as eggs, and at a temperature ranging 
from 38° down to 30° F. It is very common practice now to 
place cheese in cold storage when only eight or ten days old. 
At this age it is not properly cured, and should not be placed in 
a lower temperature than 38° F. The temperature may be grad- 
ually lowered after a month or two, and at an age of three or 
four months the temperature of the room should reach 30° F., 
but should not go any lower. If the temperature is carried much 
below 30° F. for any length of time it will injure the texture of 
the cheese, and even at 30° F. some claim that it makes the cheese 
"short" or brittle in texture. Cheese will freeze so as to be un- 
fit for market at about 20° to 25° F. The reason why cheese 
should not be placed in too low a temperature while new, is that it 
may not ripen or "cure up" properly, and is liable to develop a 
bitter flavor. It must be remembered in considering this sub- 
ject that cheese is of many different kinds and widely varying 
quality. What is said above refers to an average make of Amer- 
ican Cheddar cheese. (For further information on the cold cur- 
ing of cheese see chapter entitled "Cheese in Cold Storage.") 

Apples are stored in large quantities during the fall and win- 
ter months: The quality of the fruit should be prime, and not 
too fully matured. It is customary to place apples in egg rooms 
as fast as eggs can be removed in the fall, and no bad effect will 
result. Apples and eggs should not, of course, be placed in the 
same room together, but when a room is emptied of eggs it is 
customary to fill it with apples. After the apples go out and 
before again filling with eggs, the room should be thoroughly 


whitewashed. (See chapter on "Keeping Cold Stores Clean/') 
There are many different varieties of apples, and some of them 
require special treatment in cold storage, but the generally ac- 
cepted temperature for apples for long-period storage is 30° or 
31° F. Some apple men prefer higher temperatures, and get 
good results, but the lower temperatures are the favorite. Ap- 
ples should not be quickly cooled when placed in cold storage. 
If a week or two is consumed in reducing them to the correct 
temperature so much the better. (See chapter entitled ''Apples 
in Cold Storage.") 

Lemons and oranges are very successfully cold-stored at 
temperatures of from 35° to 40° F. Lemons are very sensitive to 
cold, and may be seriously damaged if the temperature ap- 
proaches near the freezing point. Thirty-eight degrees is thought 
best for lemons. Oranges are carried at a temperature of 34** 
or 35° F. Lemons and oranges must be stored by themselves, 
and carefully isolated from products like eggs and butter. It 
is best not to handle these in the same building imless through 
a separate outside entrance, as much damage results to eggs and 
butter if flavored with the odor of citrus fruits. Some promi- 
nent cold storage houses have been very heavy losers from being 
obliged to pay for damage from this cause. 

Dried fruit and nuts, flour, and other goods known as gro- 
cers' sundries, are now a large item for cold storage in some 
wholesale centers. This business comes largely from the wholesale 
grocers and commission men. These goods are stored at a tem- 
perature of 35° to 45° F. The storage of furs, woolens, etc., 
is an important and lucrative business in many cities, and where 
the volume of business is sufficient a room may be set aside for 
the purpose, and made to pay well. Any temperature below 40° 
F. is all that is necessary for this class of goods. Potatoes may 
be kept in cold storage at a temperature of 34° F., and carried 
until spring in prime condition. Potatoes freeze easily, and are 
entirely ruined when frozen, so the temperature must never 
touch the freezing point. Cabbage may be carried some time in 
a green condition, at a temperature of 33° F. Freezing will not 
damage cabbage materially if the frost is drawn out slowly. The 
freezing and storage of poultry is a remunerative business, and 
much poultry is handled through cold storage. The freezing 


may be accomplished at 12° and 15° F. with good results if 
stock is freshly killed and in small packages. For temporary 
holding without freezing a temperature of 30° F. is best. Poul- 
try can only be held a few weeks at this temperature, a month 
to six weeks being the extreme limit. Beer and meat are han- 
dled by some houses. Beer should be held at 35° to 38° F., and 
meat at 30° to 38° F., depending on length of time it is to be 


The rates to be obtained for storing different products vary 
with the locality, competition, etc., but the following will serve 
as a guide. These rates are mostly higher than average rates 
on carload lots, but will serve as a guide to those not familiar 
with local rates. Each locality has its own rates to some extent : 

Per Season Season 

Month. Rate. Ends. 

Eggs, per 30 doz. case $ .15 $ .60 January i 

Butter, per 100 lbs 25 i.oo January i 

Cheese, per 100 lbs 20 .75 January i 

Apples, per barrel .15 .60 May i 

Lemons, per box 10 .40 July i 

Oranges, per box 08 .30 July i 

Dried Fruit, per 100 lbs 08 .35 November i 

Nuts, per 100 lbs 10 .40 November i 

Furs. Coats, etc 2.00 January i 

Potatoes, per 100 lbs 10 .35 April i 

Cabbage, per ton 1.50 4.00 April i 

Poultry freezing, per cwt 25 i.oo April i 

Beer, space rented at 15c. per cubic foot per year. 
Meat, per 100 lbs., 15c per month. 


To show the prospective earnings of a small house we will 
take one of twenty-five carloads capacity operated on the "grav- 
ity brine" system, and assume that we secure the first year half 
its capacity, or twelve cars of eggs. Twelve cars of eggs equal 
4,800 cases. If we secure a season rate on all, at the carload- 
rate of 50 cents, this will give us a gross income of $2,400. Oper- 
ating costs are difficult to obtain even with the simple ice and 
salt system owing to widely varying circumstances under which 
plants operate. An estimated cost of the ammonia or other mechani- 
cal systems is out of the question as the item of attendance alone 


is never the same. The operating expenses of the house will be 

about as follows : — 

Tee, 500 tons, 3cx: $150.00 

Salt, 30 tons, $6.00 180.00 

Power 125.00 

Labor 150.00 

Interest, insurance, repairs, etc. on an investment of 

$8,000 at 8 per cent $640.00 

$1,245.00 • 
From these figures it is seen that with our house half full 
of goods, the business would pay a fair profit above actual ex- 
penses. It may be well to note here that it costs practically as 
much to operate a cold storage house half filled with goods as 
it would if completely filled. The only difference is a small labor 
item of the handling, and the cost of cooling the extra quantity 
of goods in the first place to the temperature of the room, both 
very small items. The moral of this is that the cold storage man- 
ager should aim to have his house filled every year. If apples 
are to be had as the eggs go out in the fall, the income for the 
year is materially increased with little cost, as apples require only 
a small amount of refrigeration during the cool weather of fall 
and winter. 


A few words of advice to prospective investors regarding 
the danger of experimenting in cold storage construction. It is 
dangerous from the fact that a failure means the damage of a 
very valuable product, and a consequent heavy money loss. The 
most absurdly foolish schemes have been tried by men with no 
practical or scientific information, and the result has been what 
any thorough-going cold storage man could foresee, — either flat 
failure or no tangible results from the experiments tried. Some- 
times it occurs that the would-be cold storage man thinks to save 
architect's and engineer's fees by planning his own building, or 
by taking some of the plans and ideas which appear from time 
to time in the agricultural or trade papers, and working them over 
to suit his case. It is the author's positive opinion that four 
times as much money is wasted in this way as there is saved. 
Xo two houses properly use the same construction and arrange- 
ment, and each case requires special study by the designer in 


order to do it justice, and he is a poor engineer indeed who can- 
not save twice his fees to his client. The above advice is given 
with an intimate knowledge of the subject, as the author has 
spent much money on experiments and tests of various kinds, and 
never expects to be properly reimbursed for the time and effort 
expended. All lines of industry are more and more specialized, 
and the planning and equipping of a cold storage house is just 
as much a special business as the buying and selling of produce. 

As has already been pointed out, the results possible to at- 
tain by the use of ice are equally as good, within certain limits, as 
may be obtained by employing the ammonia or mechanical sys- 
tems. The ice and salt system has the advantage of being 
cheaper to install, cheaper to operate, and a better control of tem- 
perature is possible. These are all very good reasons why the 
ice and salt system should be adopted where ice is a sure crop, 
and can be put in the house at a moderate price. There is abso- 
lutely no question about the results obtained from storing goods 
in such a house, well-built and properly managed. The most 
perfect results possible in refrigeration may be obtained, and at 
a small cost as compared with the mechanical systems. Where 
manufactured ice is in use the small cold storage house, butcher, 
produce dealer, or any other business requiring refrigeration in 
comparatively small amounts, can in many cases obtain the best 
results at a lower cost by the use of ice and salt than by the in- 
stalling of a small machine. Besides this they are absolutely 
safe against a breakdown. 

The question is often asked, "How long will a cold storage 
house and its equipment of piping and iron work remain in good 
operating condition?" No positive answer can be made, as a 
great deal depends on the building and the apparatus, and the 
way it is handled and cared for. The average life of a cold stor- 
age building and the insulation should not be essentially different 
from that of arw ordinary building of the same construction, and 
this means that it will last indefinitely. The equipment, with 
ordinary repairs, would do good service for from fifteen to twen- 
ty-five years, probably longer under favorable conditions. An 
ice house will remain in good condition for from ten to fifteen 
years, and it is probable that it would be serviceable for the pur- 
pose for a much longer time. 




An important factor in the cost of constructing and cost of 
refrigerating cold storage rooms, as independent rooms, or as 
a complete warehouse, is the relation of dimensions (length, 
breadth and height) to area of outside exposure. This point 
is often lost sight of in the design of refrigerated structures, 
and the desire to gain all the space possible on main floor some- 
times leads to some very absurd arrangements from a theoreti- 
cal, practical or business standpoint. The installing of first-class 
elevator facilities in a cold storage warehouse is very important 
and with a fairly high rate of speed and a commodious car, space 
on the floors above is practically as valuable as space on the 
ground floor. The idea that storage rooms should be low, say 7 
feet to 9 feet, has often been carried to an unwarranted extreme. 
It is where rooms are to be used for temporary purposes only that 
it is desirable to have the rooms low to avoid unnecessary labor in 
handling the goods. Rooms for long period storage purposes as 
a general rule should be made from 10 feet to 12 feet in height; 
not only as a matter of economy of space and cost of construc- 
tion, but the circulation of air in the room is much more perfect. 
This is especially true of direct piped rooms. The importance of 
this subject has been so often overlooked in the construction of 
cold stores that it has been thought advisable to direct attention 
to it here. The relation of the cubical contents of a building to 
its outside exposure or superficial area is readily appreciated by 
noting a few figures, as follows : 

Take three rooms or buildings of equal storage capacity, with 
cubical contents of 1,000 cubic feet, and whose three dimensions 
vary. The cube with length, breadth and height each 10 feet 
(see Fig i) has an outside exposure of 600 square feet. 


FIG. I. — BxLxH equals i,ooo cubic feet. 

loxio equals loo; 100x6 equals 600 sq. ft. 
Ratio of cubical contents to outside 
exposure 1,000 to 600. 

Comparing with another rectangular space of equal capacity 
— whose breadth is 10 feet, height 7'6" and length I3'4''. (See 
Fig. 2.) 

FIG. 2. — BxLxH equals 1,000 cu. ft. 

I0'xi3'4"x2 equals 266 2-3 sq. ft. 

lo'x 7'4"x2 equals 150 sq. ft. 

7'6"xi3'4"x2 equals 200 sq. ft. 

Total 616 2-3 sq. ft. 

Ratio of cubical contents to outside 
exposure 1,000 to 616 2-3. 




It will be noted that the change of dimension in this case 
is but slight from the cube, so the increase of outside exposure 
is only 2.77 per cent. 

Taking another and more pronounced departure from the 
cube and still retaining the capacity of 1,000 cubic feet, where 
the breadth is 6'8", length 25V and height 6'o" (see Fig. 3). 

FIG. 3. — BxLxH equals cu. ft. 

6'o''x25'o"x2 equals 300 sq. ft. 
6'8''x25'o''x2 equals 333 sq. ft. 
6'8"x 6'o"x2 equals 80 sq. ft. 

Total 713 sq. ft. 

Ratio of cubical contents to outside 
exposure, 1,000 to 713. 

To sum up the comparison of the cube with the other two 
rectangular rooms or buildings would be as follows : 

Fig. I 
Fig. 2 
Fig. 3 

Cubical contents 
in cubic feet. 


Superficial area 
or outside expos- 
ure in square 

616 23 

Percentage of 

increase over 



The result is important in view of the fact that the loss of 
refrigeration from heat leakage through the walls is on the 
average probably three-fourths of the total amount necessary 


to supply and maintain temperature in cold storage rooms. The 
amount of heat leakage will be directly proportional to the ex- 
posed outside surface or superficial area of the room or house. 
The cost of insulation which is usually figured by the square 
foot of wall surface is also increased proportionately, and the 
cost of building is also greater. The cost of insulation and cost 
of cooling to make good the heat leakage will be 18.83 P^^ cent 
greater if the room or building is built as in Fig. 3, than if built 
in the form of a cube, as in Fig. i. Therefore, in the design of 
cold storage rooms or buildings, the nearer a cube may be ap- 
proximated, the cheaper the first cost and cost of operation, 
other things being equal. 

This must not be carried to an extreme which will make the 
conduct of the business laborious or expensive. Some classes of 
trade require much floor space and little height, while others may 
use a high room. For a business where many goods are han- 
dled in and out, daily, ground floor space is extremely valuable. 
In extreme cases it may be necessary, on account of expense 
and time consumed in handling, to arrange all storage rooms on 
the ground floor. To do this the advantages obtained must more 
than oflfset the increased cost of construction and operation. For 
a business where goc^ are mostly in for long-term storage a 
house of several floor^s practically as convenient, costs less, is 
cheaper to operate and requires le^ground space. 




The selection and correct use of materials for insulation is 
one of the most important considerations in the design of cold stor- 
age warehouses. It is purposed in this chapter, to condense the 
available information and data on the subject in a general way, 
describing the methods and materials as they have been used up 
to the present time. In giving the insulating values of different 
materials it is intended to eliminate mathematical formula as far 
as possible so as to serve the average cold storage man in a 
practical manner. At the same time the author will consider it 
a duty to describe apparatus used to determine these values and 
g'!ve tables of the results obtained, although seemingly complicated. 

There is no other part of cold storage work on which there 
has been a greater diversity of opinion ar^^ractice ; consequently 
a great variety of materials h^ been used in many combinations 
to serve as insulation. This is natural, because until recently the 
designers were largely cold stora^men who had designed their 
own houses, and the insulation was commonly a matter of guess 
work, personal fancy or an original idea; hence they were apt 
to think that the particular kind of insulation in their own houses 
was about the best unless it proved very bad. The character of 
the insulation in each case has been largely the result of the 
general educational standard of the individual. Some would 
content themselves with a small quantity of the cheapest kind 
of material available and literally **throw" it into place, forget- 
ting meanwhile that their insulation was a most important factor 
in the successful and economical operation of their house. Oth- 
ers have availed themselves of the best materials on the market, 
and after observing the results of their work, they know that 

♦This chapter was largely written by the Author's Associate. Chas. A. Berger, who 
also prepared tJie drawings and conducted the original tests as described. 


"the best is none too good/' when intelHgently appHed. This 
'^pioneer'' work has of course been essential to the development 
of scientific cold storage insulation. The selection of the best 
materials for a given duty was very difficult, owing to the claims 
of the manufacturers and salesmen of the various insulating 
materials, they sometimes distorting their laboratory tests of the 
non-conducting properties of various substances to suit their own 
particular material. These tests, while perhaps correct, were 
often misleading to the customer because other considerations 
besides non-conductivity must be considered. 

In connection with the foregoing we should not lose sight 
of the fact that reliable information on the subject was very 
meager up to nearly the last decade, there having been prac- 
tically no reliable literature or data published up to that time. 
The refrigerating machine manufacturers usually devoted a page 
or two of their catalogues to "approved" insulations, but they 
seldom had advanced or progressive ideas on the subject. The 
insulations they recommended were as a rule insufficient for 
economical operation. It was found much easier to sell a larger 
machine than to convince the customer that he should invest 
more money for better insulation. 

Laboratory tests of the heat conductivity of materials cannot 
be absolutely relied upon when these materials are to be used 
for cold storage insulation. These tests are usually made under 
high temperature conditions and relatively low humidity, such 
as steam pipe covering. Such conditions do not obtain in cold 
storage work where the lower temperatures and relatively higher 
humidity are the conditions. Numerous articles and papers have 
been written for the trade periodicals and read before various 
associations on the subject of insulation. Some of these articles 
are very theoretical and are based altogether too much on labor- 
atory test tables of heat conductors, which makes them almost 
useless for practical application in cold storage construction. It 
must be said, however, that they are along the right lines as 
tniderlying the science of thermal conductivity. 

In recent years many tests of composite insulations put to- 
gether just as they would be erected in a cold storage house wall 
bave been conducted and tables compiled therefrom by experi- 
iTienters who have made the subject of insulation a study, and 


who have had much practical experience in its application in 
their capacity as designing architects and engineers. These tests 
show in many cases a wide variation in results, owing no doubt 
to the fact that the tevSts have been made under widely varying 
conditions and methods and also to the changeable factor of 
human error or personal equation in the observation of the tests. 
The w^ork of these experimenters shows much painstaking care, 
and much good has resulted in raising the standard of the con- 
struction of scientific and practical insulation. 

In order to properly apply materials for the purpose of pre- 
venting heat transmission, it is necessary that the theory of heat 
and its behavior should be understood. It is proposed therefore 
to review the simple natural laws which underlie this subject. 


According to the modern scientific theory, heat is not a sub- 
stance, but a form of energy; a mode of motion or vibrations, 
like light and sound. Primarily, there is but one source of heat, 
the sun, from which all lesser sources receive their supply by 
radiation. These lesser sources are: Friction, percussion and 
pressure, terrestrial heat, molecular action, change of condition, 
electricity and chemical combination. Like all other forces of 
nature that are manifested to us, the molecular, kinetic energy 
of heat has a tendency to equilibrium, or like water, to seek 
its. level ; but unlike w^ater, it cannot be confined by any known 
material or substance. If there is a diflFerence in temperature on 
the two sides of a wall, heat will pass through that wall until 
the temperature on both sides is the same, regardless of what 
the wall consists of. The flow of heat through a wall can, how- 
ever, be controlled to a great extent by using materials that will 
retard its passage. 

The transmission of heat is affected in three different ways : 
first; by radiation; second, by convection; and third, by conduc- 
tion. Radiation is the direct passage of heat through the air 
from one body to another without perceptibly heating the air, 
and is manifested to the senses by the heat which is felt when 
standing by an open fire. By radiation, heat is thrown off in 
every possible direction from every point of a hot body. In an 
inclosed air space with different temperatures as shown in Fig. 
I, the radiant, heat would pass from the high to the low tem- 



peratiire side directly across the space indicated by arrows. The 
scientific definition of radiant heat is that it is in the nature of a 
wave motion communicated through an exceedingly subtle ether, 
which is supposed to pervade all space, and that it is obedient 
to tiie laws of refraction, reflection, polarization, etc., the same 
as light. 

Convection of heat is the transfer from one place to another 
by the bodily moving of the heated substance, such as when air, 






















V J 







10' r 


water or any other gas or fluid comes in contact with a heated 
surface; the particles touching the heated surface be'come warm 
and lighter, therefore ascending and giving place to the colder 
and heavier particles below. This action is illustrated by the 
heating of rooms with stoves ; the air as warmed rises to the top 
of the room and its place is taken by the colder air from below. 


The principle of convection, or circulation as it is generally un- 
derstood, is shown by Figs. 2 and 3, where the air in the inclosed 
space with one side warmer than the other, being heated on 
that side, becomes lighter by expansion and rises; as it gets to 
the top of the confined space, it passes over to and down the cold 
side where it gives up heat ; as it is cooled, it contracts and be- 
comes heavier; it then sinks and returns to its original place. 
This circulation will continue indefinitely or until the temperatures 
on both sides of the space are equalized. Fig. 3 illustrates this 
principle when a wall is subdivided into a number of such spaces, 
and the circulation becomes more complicated and retarded, pass- 
ing less heat for the same thickness of wall in a unit of time than 
a single space, as illustrated in Fig. 2. 

Conduction is a term applied to heat flowing from a warmer- 
to a colder part of a body, or if a solid substance is placed in 
contact with a body having a higher temperature, the particles 
of the substance nearest are warmed, and they in turn give up a 
portion of the heat received, to particles next to them and so on 
from particle to particle until the whole substance is heated ; this 
is accomplished without any sensible motion. A more familiar 
example of conduction is putting one end of an iron poker in the 
fire ; after a time, the other end will become heated and apparent 
to the sense of feeling. 

As heat then is not a substance but a vibration of the mole- 
cules that compose a body, and that the rapidity of these vibrations 
is the cause of the difference of temperature, it is really improper 
to speak of heat and cold as such; but it is convenient to use 
these old familiar terms in describing the phenomena, just as it is 
said that the sun rises and sets, where it is in fact the earth that 

Theoretically, all bodies and substances transfer heat by 
radiation, convection and conduction at the same time, and this 
is called complicated transfers of heat. Scientists state that 
bodies at high temperatures will lose more heat by radiation than 
by convection and conduction, and that heat radiated by a coal 
fire is estimated to be a!)OU1; one-half of the total heat generated. 
At lower temperatures, such as is dealt with in refrigerating 
work, transmission of heat by radiation is very small, and that, 
practically, convection and conduction only need be considered 


in cold storage construction. With the understanding of the 
definitions given above, it is readily seen that walls can be so 
constructed as to retard or facilitate either mode of transfer. 
This will be discussed more fully when considering insulating 


" The quantity of heat contained in a body is the sum of the 
kinetic energy of its molecules. Heat is measured quantitatively 
by the heat unit, which also varies in different places like other 
standards. The unit used in the United States and England is 
the British Thermal Unit (abbreviated B. T. U.), and represents 
the amount of heat required to raise the temperature of one 
pound of water i° F. The French unit is the Calorie, and is 
the quantity of heat required to raise the temperature of one 
kilogram of water from o° to i° Celsius. 

Some writers define the B. T. unit as the heat required to 
raise the temperature of one pound of water from 32° to 33°. 
Others make this temperature from 60° to 61°, and still others 
define it as the a;nount of heat required to raise 1/180 pound of 
water from the freezing to the boiling point. The last two defi- 
nitions give nearly the same result, and may be considered prac- 
tically identical." 

The unit of heat transmission or insulating value is the num- 
ber of B. T. U. that will pass through one square foot of a sub- 
stance per hour, per degree difference in temperature between 
the two sides of the substance. Some engineers prefer (in refrig- 
erating work) to use a time unit of one day (24 hours) instead 
of one hour in their values. This is perhaps more comprehensive, 
as refrigerating capacity is usually figured per day, and it also 
is an advantage in that the values are more likely to be expressed 
in whole numbers and less in decimals. 


Many laboratory experiments conducted by noted physicists 
during the past century have given us tables of heat conducting 
properties of the metal, mineral, liquid and vegetable substances ; 
these tables vary from one another, depending upon the methods 
used and the nature of the experiments. These experiments 
demonstrate that the metals are the best conductors of heat; 

* Dr. J. E. Sicbcl, **Compend of Mechanical Refrigeration.' 


that the vegetable and animal substances are the poorest conduc- 
tors of heat, and that between these the minerals and liquids are 
all arranged in varying degrees of heat conductivity. 

The following table of the relative heat conductivity of a 
number of substances is taken from Sir William Thompson's 
article on "Heat" in the Encyclopaedia Britannica, reduced to a 
unit of conductivity of one for water; this includes authorities 
that he regarded as reliable on that subject. Part of this table 
was taken from experiments made by Peclet, whose table is also 
given below in B. T. units : 

Article on "Heat" in Encyclopedia Britannica. 

" Copper 455. 

Iron 80. 

Sandstone 5.34 

Stone 2.95 

Traprock 2.075 

Sand ' 1.31 

Water i. 

Oak (across fiber) 295 

Walnut (along fiber) 24 • 

Fir (along fiber) 235 

Walnut (across fiber) 145- 

Fir (across fiber) 13 

Hemp cloth (new) 072 

Wool (carded) .061 

Hemp cloth (old) 0595 

Writing paper (white) 0595 

Cotton wool 0555 

Eiderdown 054 

Gray paper (unsized) 047 

Air 0295 

Cork 0145 

Note: The figure for air has been fixed by J. Clark Maxwell's bril- 
liant investigations. He gives its conductivity at 1/20,000 that of copper, 
as 1/3,360 that of iron, a determination reached by mathematical deductions 
' from the kinetic theory of gases. 

In the latter part of the eighteenth century, Count Rumford, 
who did much work in the experimental study of heat, maintained 
that liquid.s had no conducting power at all, but gained heat by 
convection only. This was afterward found to be incorrect, as 
shown in the above table, and shows in fact that water stands 
next to the mineral substances in conductivity. 

As to quantitative or rate of transmission, the following table 
from experiments made by M. Peclet* gives the amount of heat 
in B. T. units transmitted per square foot per hour, througli 
various substances one inch in thickness. He terms these poor 

* Peclet's "Traite dc la. Chaleur/* IV Ed., Tome 1, Pgs. 542 to 555. 


conductors (to distinguish them from the metals). The results 
of these experiments are considered quite reliable, as they are 
used extensively by heating engineers of Europe in their calcu- 
lations for the heating of buildings. The experiments were made 
by heating one side of the substances with hot water, and cooling 
the other side with cold water, the difference between the tempera- 
ture of the two sides being i° F. 


By M. Peclet. ^irtlS/itl^S! 

Gray marble, fine grained 28. 

White marble, coarse grained 22.5 

Limestone, fine grained 14.8 

Limestone, coarse grained 10.5 

Glass 6. 

Brick 5.6 

Terra cotta 4.8 

Plaster of paris Z-^ 

Sand 2.2 

Oak, across the grain 1.7 

Fir, across the gram 0.75 

Fir, along the grain 1.4 

Walnut, across the grain 0.83 

Walnut, along the grain 1.4 

Guttapercha 1.37 

India-rubber 1.36 

Brick dust, sifted 1.33 

Powdered coke 1.3 

Iron filings • 1.26 

Cork I. IS 

Powdered chalk 86 

Powdered wood charcoal 63 

Straw, chopped 56 

Powdered coal, sifted 54 

Wood ashes 5 

Canvas, new^ 41 

Calico, new 40 

Writing paper ' .34 

Cotton, raw or woven .32 

Eiderdown 31 

Blotting paper 26 

In an article written by Prof. John M. Ordway*, on "Non- 
conductors of Heat," which treats of insulation tests conducted 
on steam pipes, he subjoins the following table of non-conduc- 
tivity of various substances. The figures in the last column are 
for covering, one inch thick, with a difference of 100° F. on each 
side of the covering. In most of the tests a stream of water at 
about 176° F. was kept running through the heater. In some 
cases the source of heat was steam at 310° F. as stated : 

• Ice and Refrigeration, October, 1891, Page 216. 




Net cubic in. 
of solid 
Non-conductors one inch thick. matter in 100 

Still air 

Confined air • 

Confined air=3io° 

Wool=3io° 4.3 

Absorbent cotton 2.8 

Raw cotton 2 

Raw cotton i 

Live-geese feathers=3io° 5 

Live-geese feathers=3io*' 2 

Cat-tail seeds and hairs 2.1 

Scoured hair, not felted 9.6 

Hair felt 8.5 

Lampblack=r3io** 5.6 

Cork, ground 

Cork, solid 

Cork charcoal=3io° 5.3 

White-pine charcoal=3io*' 1 1 .9 

Rice-chafF 14.6 

Cypress {Taxodium) shavings 7 

Cypress {Taxodium) sawdust 20. i 

Cypress {Taxodium) board 31 .3 

Cypress {Taxodium) cross-section 31.8 

Yellow poplar {Liriodendron) sawdust 16.2 
Yellow poplar {Liriodendron) board.. 36.4 
Yellow poplar {Liriodendron) cross-sec. 30.4 

"Tunera" wood, board 79.4 

Slag wool (Mineral wool) 5.7 

Carbonate of magnesium 6 

Calcined magnesia=3io*' 2.3 

"Magnesia covering." light 8.5 

"Magnesia covering," heavy 13.6 

Fossil meal=3io° 6 

Zinc white=3io° 8.8 

Ground chaIk=3io° 25.3 

Asbestos in still air 3 

Asbestos in movable air 3.6 

Asbestos in movable air=3io° 8.1 

Dry plaster of paris=3io° 36.8 

Plumbago in still air 30.6 

Plumbago in movable air:=:3io° 26. i 

Coarse sand=3io° 52.0 

Water, still 

Starch jelly, very firm, " 

Gum-Arabic, mucilage. " 

Solution sugar, 70 per cent. " .... 

Glycerin. " 

Castor oil, "• 

Cotton-seed oil, " .... 

Lard oil, " 

Aniline, " 

Mineral sperm oil, " .... 

Oil of Turpentme. " 

Heat units trans« 

mitted per sq. ft. 

per hour 






































A careful study of these tables shows that still air is one 
of the poorest conductors of heat available for practical pur- 
poses. The distinction between confined air and still air, and 
the greater conducting qualities of the former has not been gen- 
erally understood, and it is perhaps on this account that air 
space construction has been used so much for cold storage insu- 
lation. Note what Dr. Hampson, an English authority, has to 
say on air spaces. The conclusions reached by him have also 
been demonstrated by the author and other experimenters in this 
country, and the result is the present tendency to use materials 
which will subdivide the air into an infinite number of spaces. 
As insulators against heat Dr. Hampson, in a series of lectures 
at University College, Liverpool, England, sums the various sub- 
stances up as follows : 

Conduction and convection are best prevented by a totally empty 
space intervening between the external objects and the internal cold ob- 
jects — in other words, by having a vacuum between two air-tight walls. 
Radiation can be to a great extent prevented by having a bright metallic 
surface between the inside and outside. The efficiency of this combina- 
tion was shown in one of the silvered vacuum vessels designed by Pro- 
fessor Dewar, which contained liquid air which had been made half a 
week before. Where such an arrangement was impossible, the best thing 
to do was to fill the insulating space as far as possible with the substance 
that had the smallest capacity for conducting heat. Iron has about one- 
seventh the conducting power of copper, wood or other organic substances 
still less, ice has only about one two-hundredth, and air not more than a 
twenty-thousandth part of the conducting capacity of copper. Air, there- 
fore, is the best insulating substance available ; but its value depends upon 
its stillness, for if free to move in spaces of considerable size, it will be 
in constant circulation, convection currents carrying in heat from the 
warmer outside walls to the colder inside walls of the insulating spaces. 
These spaces should therefore be very shallow, so that the viscosity of 
the air, which is very small, will be able to prevent it from moving. 
It is their possession of a large proportion of air, prevented by septa or 
filaments from moving, that determines the excellence of the usual insu- 
lating materials, such as eider down, wool, feathers, hair, chaff, cork, 
slag-wool, asbestos, charcoal, wood, sawdust, etc. 


Physicists seem to have proved that a vacuum is a poorer 
conductor of heat than air, and a reference is made to it by Dr. 
Hampson, as noted above. This was discussed by Dr. H. W. 
Wiley in an address before the American Warehousemen's Asso- 
ciation convention at Washington, D. C, December, 1903, and 
as it is interesting in connection with the subject, we quote in 
part as follows :* 

•Reported in Ice and Refrigeration, January, 1904, page 35. 


There is one practical suggestion which these theories present, namely, 
that a vacuum is by far the best protection against radiation that has 
ever yet been discovered. Sawdust, shavings, cork, cloth, wood and many 
other substances have been extensively used to protect cold spaces against 
radiation, but none of these have anything like the obdurating properties 
of a vacuum. Liquid air and even liquid hydrogen contained in a vacuum 
receiver, that is, a receiver surrounded by a vacuum, retain their liquid 
state for hours and even days. There is, of course, a loss by radiation 
and evaporation from the exposed surface, because pressure dare not be 
used in confining these bodies, but this loss is comparatively slow. The 
vacuum becomes an almost perfect protector against heat. If, therefore, 
the refrigerating rooms which you use could be surrounded with a vacuum 
space, it would most certainly reduce very largely the expense of main- 
taining the low temperature. There are, of course, practical objections to 
the use of a vacuum for this purpose of a very serious character. The 
two chief objections would be the difficulty of maintaining an airtight 
space so that there would be no leakage into the vacuum and the enormous 
pressure upon the walls of the vacuous space produced by the atmosphere 
itself. It is easy to construct a steam boiler which will bear a pressure 
of from 400 to 600 pounds to the square inch, and it ought not to be dif- 
ficult to construct a vacuous space around a refrigerating room which 
would resist a pressure of 15 pounds to the square inch. The expendi- 
ture and the energy required to evacuate this space and keep it practically 
free from air would, in my opinion, be profitably expended, providing the 
two conditions of imperviousness and pressure could be regulated. The 
idea is at least worthy of experimental trial and it is hoped that some of 
you will submit it to a practical test. 

Mr. James Wills of New York has made a practical trial 

of a vacuum as insulation for brine piping with good results, 

but it has not been learned that the experiment has met with 

sufficient success to warrant its adoption on the more recent work 

constructed under that gentleman's supervision. 


M, Peclet proved experimentally that the rate of transmis- 
sion of heat was directly proportional to the difference of tem- 
perature on each side of a substance, and was inversely pro- 
portional to the thickness. That is ; if a substance one inch thick 
transmitted say, one B. T. U., the same substance two inches 
thick would transmit one-half B. T. U. under same conditions. 

The results of later experiments, on poor conductors and on 
those used in combination (such as used in the construction of 
cold storage warehouses) show, however, that these conclusions 
are in doubt. John E. Starr, in an article* on results of tests, 
conducted by himself, states : "It is a well known fact that the 
amount of heat transferred per degree of difference increases 
somewhat with each degree of increase of difference of tem- 

"Non-coRductors of Heat," in Ice and Refrigeration, July, 1891, page 37. 


perature." This same experimenter illustrates this principle 
graphically by a diagram of tests* showing ice meltage in ordi- 
nary domestic refrigerators at various differences of temperature 
between inside and outside. If the transmission had been directly 
proportional, the plotted curve on the diagram would have been 
a straight line. 

This increase of transmission per degree of difference as the 
difference increases is also shown by a chart published in Ice 
and Cold Storage (British), March, 1901 (see Fig. 4, page 48), 
of results of tests with eight different constructions of the same 
thickness. It is a matter of regret that the methods of testing 
were not described in this case so that we could judge of their re- 
liability. Referring to the chart it will be found that the line 
plotted for the rate of transmission of each material is a curve, 
having a range of temperature difference of 80° F. Calculating 
down to per-degree difference at each end of the chart and divid- 
ing the result by the range of difference (80° F.) shows co- 
efficients of increase, varying from 25 to 50 per cent. 

The author, in conducting a series of tests in 1900 and 1901 
(which will be described further on), obtained results that tended 
to prove the correctness of the observations cited above. This 
co-efficient of increase varies for different substances and combi- 
nations of materials, and to determine these co-efficients accu- 
rately would be a difficult task indeed. From the above facts it 
is obvious that the co-efficients of heat transmission obtained by 
tests of substances which were made under a temperature dif- 
ference of only one degree, are too small for practical application, 
and tliey should be increased about 50% when used for de- 
signing cold storage insulation. This is of increasing importance 
when we consider that the tendency of modern cold storage prac- 
tice is toward maintaining lower temperatures, often resulting 
in a difference of temperature of from 70° to 90° F. between 
inside and outside of walls. This is comparatively a high range 
of temperature and the conditions to this extent are similar to 
heating work. 

That transmission of heat through any substance is not in- 
versely proportional to the thickness seems evident by an exam- 
ination of the following table converted from the metric system 

• "The Cost and Value of Low Temperatures," in Ice and Refrigeration, Sep- 
tember, 1891. 











by Chas. F. Hauss, Antwerp, Belgium. This writer states* that 
this table is used by Adolph Block of Hamburg, one of Ger- 
nlany*s most reliable engineers: 




IhffemiM in Teoiperfitunf— FAhivnheit 


uf Walb- 

r ■ r to* T.'r :n" 2.1' 30* 35" i 40^ 1 45=^ 50" , ^h" r-n- ,i.V ■ 70° 


n h : III s ^<i 7 -"11 '' I'll \2iVli 


JO.NO 19. 20;2I..50 24.00, 2fiMt l^>ji il _m :v.iM 

'.rAX 1 :ii ■; S'l .'.In n.^n s..>() 


11.90 l3UK>!l5.30 17.(l(|lS.Tn 2i1 JU .^2iNi 2S.80 



0.20 l.:5ii . 'Ji :^ '.i'^ " !■ "h) 


&,10 10.40 lLt;5 13 0014^ ISM iLi.lKl. 18.20 


0.22 I III J-^'i :i;v' ^ ^11 -.'fii 


7.70 ^i.'^ 10.00 1 LOO 12.110 i;i 20 14.30 \^M 

Brict 2.5' 

O.lHOlHl l.^ii 2 7<^ Ar^\ 4 Vi 


6.30 7.20 RIO. 9 00! M 10,8t> H,TO 12.60 

' 30- 

0. Its 0.80 l.i^i L' l£? -I -II 1 i"'i 


5.e0 (i.40 7/20 SM !i.80 9.60 10 40,11.20 

Wnlla . 3.V 

0.13O.f>5! LIPi ]'JV >jf --J 


4.55 5,20 5.S5, 6.50 i 7 15 7 &0 8,4.11 9.10 


0.12 O.eo 1.2fi ].Si> J Itf :!.iir] 


4,30 4.80' 5.40 6.00 1 6.60 7 20 7.80- .H.4fl 



O.S.'i 1,10, Lli5 2 20 2.7.0 


3.a5 4.40' 4.95I 5..1OI 6.05 li.OO 7.l5| 7.70 


2.25: 4.50 

6.75 9.00]l2.i 


1 5.75 1 1 S .00 20. 25 ! 22 .^l 24 .75 27.00 2^ 2.V 3 1 .50 





5.H5 7.?^0 !^7^ 

n 7<» 

1 ^ -i"^ 1 -^ '.'> 17 9V |rr.VI 21 .45 23.40 25.25 29.30 





5.2.^ 7.(10 - :-7 

J 1 1 ",.i 1 

IJ J- ill XI 1:, „', 1; .VI iy^25 21.00 22 JS 24.60 



032! 100 


4.m 0.411 INI 

•r 1^1 

I-. Jii L'-.ii U.lii liHXl'l7/iOnK20 2tLW'22.4O 




st.9fi 4:?.v ^^f* : -■■. 

■v 711 

!■• r^ II .: ir, n "HI I.'t^V 17.40 !,t K.V 30.30 

For Linii'- 




Ej^ii :;'iii '1 :<'■ •• -'i 

" ...ii 

•' [0 III JM II ii'< 3:7<Hi E [ :yi \r,yj\ li.^hfm^ao' 

stonp Jidil M' 



l^lJi :', 141 I -.1; ,1*11 

7 .'M 

y [0 'HHi III jn ]:,\*\ [\[Ji |i.4il ]Vipii:irt.SO 





2.;^> ;.i.:>ii t in .7 7ii 


7.70 •s.,'-j» 111. Ill ]]An.i i:.(ni \.i]-jf\ 1 4. :ki 1.5.40 




2jOO 3.1HI -ISKf .7 IB* 


T.Olli s.<Kp ii.Ui lO.iJfi 11.(10 l^m i:s.<Mi, 14.00 




J. 90 2-^"» :i -.'^ t :-7 


nn\ 7Mt s .v> i>,.-,(i, i(i.,v>. 1 1 4(1 1 2.:i.-j! 13.30 

Solid nmrtifr If '-21 VO^nO 3,00 

6.00; 9,00 12.00 \bm ItJ.OO 21 IW 24.09 27.00' 30.00 ;i;i.{JO 3000 m.m 42.00 

4.SOI 7,30 9,fi012.W» 14 40 lis .Ml J»,20 21. fiO 24.00 21.00 2S..'*I31.20 33. IM) 


JouitJ with 1 

: 1 



dtiuWe flwini tKO7l0.iV 0.70 i.a^ ].m \.7^ 


2.45. 2.80! 3.15 3..50 

3.85 4.20 

4,5-1 4.00 

SUinc rtoor aa 



urdif-3 L20 UOO ^ DO, 3.00; 4.€0 A.OO 



b.DO 9.00 10.09 

ll.OOi 12.00 

13.00 14.00 

Hpnkji bid un I ' 1 


1 ' ' 1 1 

«,rth 0,1*0.80 id 2.40 

3.30! 100 



6.10 7.20; g.00 8.80 9.00 10.40111.20 

rUnkfl laid an I 1 1 

' ' i ( 1 1 

iuphdt 0^1:00 2.00 3.00 4.00 5.00 


7.001 8.D0 9.00 10.00 il 00 12.00. 13.00 M.OO 

Arrhwithiiir ' | 

mnt^ 10.09 0.15 1 0.90 i.v> 

i,fiO 2.2s 



3W 4.a5 4.50 4.95 

5.40, 5M ^M 

Sti;m» hiid on 






0^ 0.401 OJO'j^ 

Lm 2m 



3J0i 3.60 1 4.00! 4.40 

JM 5J0l 5.60 


8 JoLBt with 

single floore 











5.00 5.50 




.Arches with 

air spaces 











7.00 7.70 




Windows! Single 

11.00 S.OOilO.OOi 15.00 20.00l25.00i30.00;35.00i40.0b45.00|50.00 55.00,60.00 

65.00 70.00 

iDouble I0.4612.30I 4601 7.05| 9.20111.50 13.801 16.10il8.40i20.70123.00|25.30|27.60 


Skylights 1 Single 11.06;5.30|10.60 15.90 21.20 26.50!31.80i37.00i42.40:47.70153.00l58.30i63.60 




















Dif. in Temperature^ 


t 1° 

2.001 4.001^.001 8.OO1 10.00112.00114.001 16.00118.00 20.0022.00 24.00|26.00|28.00 
5" I 10° I 15" 126° I 25" I 30" I 35° I 40°| 45" | 50" | 55" | 60" | 65" i 70" 

This table is of limited value for cold storage work, but 
serves to show the great variation in results obtained by different 
experimenters. It will be noted that this table is based on M. 
Peclet's first proposition, viz: That the rate of transmission is 
proportional to the difference of temperature on each side of the 

The fact that the transmission of heat through any substance 
is not inversely proportional to the thickness is also shown by 

•Paper read before American Society of Heating and Ventilating Engineers, 
New Yori<, January, 1904. 




the following tables after Box.* Where N. is the value in B. 
T. U. transmitted per square foot for a difference of i° F. be- 
tween temperatures each side of wall in 24 hours. 

Vi brick 4J4 inches thick N. equals 5.5 B. T. Units 

I " 





4.5 " 


IK2 " 





3.6 " 







30 " 







2.6 " 


4 " 





2.2 " 


Stone walls 

6 inches thick N. 

equals 6.2 B. 

T. I 




•« ti 








tt tt 








it tt 








tt II 








tt tt 





The following formula for calculating the amount of heat 
that will pass through a wall of a certain area is by Dr. Siebel.* 

If the number of square feet contained in a wall, ceiling, 
floor or window be f, the number of units of refrigeration, R, 
that must be supplied in 24 hours to offset the radiation of such 
wall, ceiling or floor may be found after the formula : 
R=fn (t—ti) B. T. units. 

fn (t-tj 


or, expressed in tons of refrigeration : R=: 


In these formulae t and t^ are the temperatures on each 
side of the wall, and n th^iumber of B. T. units of heat trans- 
mitted per square foot of such surface for a difference of 1° F. 
between temperatures on each side of wall in twenty-four hours. 
The factor n varies with the construction of the wall, ceiling or 
floor from i to 5. For single windows the factor n may be taken 
at 12 and for double windows at 7. (Box.) For different ma- 
terials one foot thick we find the following values for n : 

Pinewood 2.0 B. T. U. 

Mineral Wool 1.6 " 

Granulated Cork 1.3 " 

Wood Ashes i.o " 

Sawdust I.I " 

Charcoal, powdered 1.3 " 

Cotton t)7 

Soft Paper Felt 0.5 

• From "Compend of Mechanical Refrigeration," Page 181. 


If a wall is constructed of different materials having differ- 
ent known values for n, viz, n^, nj, ng, etc., and the respective 
thickness in feet d^, do, da, the value, n, for such a compound 
wall may be found after the formula of Wolpert, viz : 

di dj dg 

n=- + - + - 

lll Hj Ug 

The value of n may be obtained from any of the foregoing 
tables that are based on the transmission per hour by multiply- 
ing by 24, the number of hours in a day, and where the values 
given are for materials one inch in thickness, n and d should be 
in inches. 


It is the purpose of cold storage warehouses to maintain 
temperatures below that of the outside air, and in order to accom- 
plish this refrigeration must be applied to withdraw the heat in 
the warehouse. In doing this, as has been already noted, the 
equilibrium of temperatures is disturbed, and the transmission 
of heat through the walls from the outside into the warehouse 
takes place. As the materials of which the walls of buildings 
are usually constructed transmit heat quite rapidly, it is neces- 
sary to **line'' them with materials that w'ill retard this transfer 
to a greater degree. These materials as used and applied col- 
lectively are called ^'Insulation," as distinguished from the walls 
of the building proper, although these insulate to a certain ex- 

Knowledge of heat teaches that a perfect insulation is im- 
possible. No matter of what materials or how thick the walls 
are made, a certain amount of heat will pass through them, and 
this must be taken up by the refrigerating medium. If it were 
possible to stop all heat transmission through walls, doors, etc., 
no refrigeration would be necessary after the goods in storage 
had been cooled down to the required temperature. On the con- 
trary, it is a well established fact that one-half to seven-eighths 
of the refrigeration applied to cold storage rooms is expended in 
removing the heat transmitted through the walls of the building. 


depending of course upon the amount of goods stored and the 
frequency with which they are handled in and out. 

The great importance of proper and efficient insulation is 
evident when it is considered that all the heat passing through it 
must be taken up by the refrigerating apparatus, which, in the 
case of poor insulation, will need to be from 25% to 50% larger 
than if the insulation were first-class. This larger apparatus 
means a greater first investment than if a smaller apparatus 
could have been used, and this difference might better have been 
invested on the insulation. The additional operating expense of 
the larger apparatus would be continuous from year to year and 
would amount to many times as much as it would if first-class 
insulation had been constructed in the first place. The invest- 
ment put into good insulation has to be made but once, while 
with poor insulation the loss of refrigeration through removing 
the greater heat leakage makes a continual heavy expense. In- 
sulation should be considered in the light of a permanent invest- 
ment, same as buildings and equipment, the returns of which 
should be based on the savings effected by the lower operating 
cost. It is a great deal cheaper to prevent heat from entering 
a building than to remove it by means of refrigeration. In the 
light of what is now known concerning insulation, even though 
it is not very extensive, there is no excuse for poor insulation, 
except that ol ignorance. 


Another element in cold storage practice that will require 
the construction of first-class insulation is that goods should be 
carried at a uniform temperature throughout every part of the 
room. With poor insulation this is not possible, no matter how 
large the cooling apparatus may be, as the parts of rooms nearest 
the outside walls will be higher in temperature than those nearest 
the cooling surfaces. This condition often results in the goods 
bemg carried at a higher temperature than they should be, en 
account of danger of freezing those that are nearest to cooling 

The comparative value of the insulating materials depends 
upon their efficiency in preventing the transmission of heat from 
the outside to the inside of the building. A study of the heat 
conducting properties of the various materials and substances as 


shown by tables here given leads to the conclusion that with a 
few exceptions we must turn to the vegetable and animal sub- 
stances for this efficiency. In selecting materials of this class 
for practical insulation, we are limited by many requirements be- 
sides non-conductivity of heat. These are enumerated below in 
order of their importance, viz : 

I. — It should be odorless, so as not to taint the perishable goods stored 
in the houses. 

2. — It should have the minimum capacity for moisture, and in case 
it should become damp, it should not rot or ferment. 

3- — It should be vermin proof, and give no inducement for rats or mice 
to nest within it. 

4. — It should not be liable to inherent disintegration or spontaneous com- 

5. — It should be of light weight, not so much on account of lightness itself, 
because buildings are usually built sufficiently heavy where they 
are to be used for warehouse purposes, but because the lighter 
materials are usually better non-conductors of heat. 

6. — If used as a filler, it should be elastic so that when it is once packed 
firmly, it will not settle further and leave open spaces which will 
be almost impossible to find and costly to repair. 

7. — It should be reasonably cheap and economical of labor so as not to be 
prohibitive for general use. 

8. — It should lend itself to practical application in general work. 

There are two other requirements which need careful atten- 
tion, viz: That materials should be waterproof and fireproof. 
The best non-conductors of heat possess neither of these in them- 
selves. It is evident then that we must satisfy these require- 
ments by proper design and construction. The former of these, 
namely — waterproofing — is essential, as all materials that are 
damp or wet transmit heat more rapidly, and waterproofing is 
usually obtained by inclosing the non-conductor with waterproof 
material. The latter of these requirements — fireproofing — is 
sometimes desirable or necessary and can be accomplished by 
surroundmg the non-conductor with masonry walls or other non- 
combustible materials. The requirements above noted have been 
met to a gieater or less extent in practical work, some classes of 
insulators possessing part and other classes possessing other of 
these qualities. It is proposed to discuss some of the materials 
that are used for insulation and ascertain their good and bad 


There are a great many kinds of materials that are used as 
insulators in various localities, depending upon their availability, 


cost and abundance, and on the character and quality of the work 
for which they are to be used. It has, in the past, been the gen- 
eral practice to construct a space inside of the main wall of the 
building by erecting the studding and sheathing same inside with 
boards ; then filling this space so formed with a **filler" in a loose 
state, that would be light in weight and dry (when put in) 
without protecting it against future accumulation of moisture. 
This sort of insulation was considered sufficient and efficient for 
all purposes, without regard to durability. There is much of 
this kind of insulation now being put up, where the importance 
of the work and operating conditions would warrant something 

From the tables of experiments already given, it will be 
noted that still or perfectly motionless air is one of the best insu- 
laton^^ against heat. But to keep it motionless it is necessary to 
confine it in very small spaces to prevent circulation and convec- 
tion of heat. This is best accomplished by properly constructing 
spaces and filling them with some sort of material in bulk. The 
value of these fillers depends upon the number of minute spaces 
into which they divide the air. Their value follows closely upon 
their specific gravity; that is, the lighter the material, the better 
insulation it is, owing to the microscopically confined air in the 
cells or structure of the material itself. Again the value of these 
fillers depends upon the density to which they are packed ; it has 
been found that if they are packed too loosely they will permit 
air circulation, and if packed too close, the conduction of heat 
will increase. With all the materials at present in use, the best 
results seem to be obtained when packed to a density of from 
nine to twelve pounds per cubic foot. Starr gives a specific grav- 
ity of about .160 as being the lowest density to which a material 
should be packed. This corresponds to about ten pounds per 
cubic foot, which is, in the experience of the author, higher than 
such materials as straw, wood shavings or cork shavings can be 
packed in actual practice. In using fillers in walls, attention should 
be given as to whether or not the materials of which they are 
composed arc in their natural state good or poor conductors of 
heat. Mineral wool, for instance, is made from furnace slag or 
lock which are considered comparatively good conductors. If 
materials of this nature are packed very tight, their value as in- 


sulation is greatly lessened. Materials which in a raw state are 
poor conductors, such as straw, sawdust, wood shavings or cork 
may be packed very tight without decreasing their insulating 
value. In fact, the insulating value of such materials is increased 
by close packing. 


Such materials as chopped straw and hay, dried grass and 
leaves, chaff and hulls of the various grains have all been used 
as fillers, as described above, and under certain conditions, they 
are fairly efficient as non-conductors of heat. They are frequently 
abundant and cheap, but as the life of such substances is com- 
paratively short and the use of some of them dangerous when 
applied to cold storage insulation, they are seldom if ever used 
at the present time. In country locations and on the farm 
they are often used to considerable advantage as a packing mate- 
rial for temporary ice houses, fruit houses, etc., their availability, 
far from manufacturing centers, making them naturally fit for 
such purposes. 


Sawdust as an insulating material practically belongs with 
those noted above, but it is still used to such a large extent for 
various purposes connected with refrigeration that it deserves 
separate mention. It has been in the past in much favor and 
was used extensively for insulating cold storage warehouses on 
account of its abundance and cheapness, but as its short life and 
deteriorating qualities became evident, it was gradually sup- 
planted by more indestructible materials. There seems to be no 
preference for the sawdust of any particular wood, as they are all 
about the same in insulating value. This value is very high 
when the sawdust is dry and clean, but if it becomes damp, it 
will rot, ferment and heat, and in this state will disintegrate and 
settle down, leaving spaces at top for leakage of heat. It may 
become a nesting place for rats and mice even when the house 
is tmder the best care. The most undesirable feature developed 
by the use of sawdust, when it becomes damp, is the liability of 
a moldy or musty condition of the rooms, and this may affect the 
goods in storage. Nearly all sawdust available is from green 
lumber, and this is very undesirable for insulating purposes. 



The most useful application of sawdust is for packing ice 
in houses storing natural ice, where it is open to the action of 
the air at all times and renewed each year. For this use, durabil- 
ity is of no moment, but for modern cold storage plants, its use 
cannot be defended in any particular. It is with regret that we 
read a description of a modern packing plant in a periodical a 
short time ago, where the machinery and other equipment were 
of the best that modern refrigerating science can produce, but 
the insulation was sawdust. Even though this sawdust is in- 
closed between masonry walls, the moisture and air will pene- 
trate and cause its deterioration in a comparatively short time. 


Planing mill shavings have superseded sawdust as a com- 
mon material for insulation, as they are free from many of the 


objections that have proved very undesirable in the use of saw- 
dust. Shavino^s are specified by the author in the composite in- 
sulations designed by him, and he believes that when they are 
properly used and protected there can be no great objections 
made to them, but they should not be used in large bulk (nor 
should any filler for that matter), but rather in combination with 
several other materials, as illustrated further on. Shavings will 
not rot, ferment or settle down under similar conditions as rap- 
idly as will sawdust, because the cell structure of the wood has 
not been destroyed. Shavings are elastic and clean to handle, 
and if properly packed (about 9 pounds to the cubic foot) will 
remain in position for an indefinite period. They should be de- 


livered to the building thoroughly dry and free from bark, dirt 
or sawdust. 

Many firms, particularly in the eastern and part of the mid- 
dle western states, make a practice of putting up shavings in 
bales This is a great advantage, both for shipping and handling, 
as it permits of their use at points distant from their manufac- 
ture. They are put up in compressed bales weighing 80 to 120 
pounds, ten and fifteen cubic feet per bale, respectively, and have 
the appearance shown in Fig. 5. The demand for shavings for 
fuel and other purposes makes them extremely hard to obtain 
in some locaHties during the fall and winter, and this difficulty 
will no doubt increase with time, as the settled portions of our 
country are being rapidly denuded of forests. The shavings of 
the soft woods are preferable, as they are less brittle and lighter 
than those from the hard woods. It is also preferable to use 
shavings from some odorless wood, such as spruce, hemlock, 
whitewood, etc. 


One material much used is commonly known as mineral 
wool, granite rockiwool, or rock cotton, in this country, and as 
silicate cotton in England. The mineral wool is usually made 
from the slag of blast furnaces, with limestone added; and the 
rock wool or rock cotton, from granite and limestone. The prin- 
ciples involved in manufacture are the same in either case and 
the process is comparatively simple. The rock is first crushed, 
then mixed with coke and fed into furnaces, where it is fused 
at a high temperature, about 3,000'' F. The molten slag or lava 
is then run out at the bottom of the furnace through a high pres- 
sure steam blast which blows it into fleece or wool, much re- 
sembling sheep's wool, except that the fibers are brittle. These 
fibers are very fine, and interlace each other in every direction, 
forming innumerable minute air spaces. In common slag wool 
about 92% of the mass consists of air spaces and in the best 
rock wool the proportion is about 96% when it is very lightly 
packed. It will be seen that for this reason it is a very good in- 
sulator, regardless of the fact that it is made from a material 
having a comparatively high conductivity. Used as an insulator, 
it should be free from "shot" and all other solid pieces, as much 
as possible. It has the qualities of being vermin and fire proof 


and is not liable to decay, but if it is packed too tightly in the 
walls, its brittleness will cause it to disintegrate, which decreases 
its insulating value. It should not be packed closer than about 
twelve pounds to the cubic foot. Mineral wool will absorb mois- 
ture quite freely, and it is stated 'by some authorities that if it 
becomes wet and then freezes, the water that has penetrated the 
air cells of the fibers, will expand and break the structure of 
the material into a granulated mass, which will settle or pack 
down, and in this state it is a poor insulator. One of the chief 
objections to mineral wool as a filler is its difficulty in handling, 
as the fibers will prick the skin and in a very short time will cause 
the hands to become sore, but the more important objection is 
the minute particles of wool floating through the air as it is 
handled, making it bad for the eyes and injurious to breathe. 
It is for this reason that workmen dislike to handle it, and this 
dislike indirectly causes the work to be slighted and poor insula- 
tion is the result. Owing to its nature, mineral wool or any of 
its manufactured products are very desirable as a retardent to 
rats and mice, and it is valuable to use in protecting other ma- 
terials from their ravages. Two inches of this material on the 
exterior of an insulated wall makes it mouse and rat proof. 

There has been, in the last few years, a tendency to manu- 
facture insulating material that would be portable, easily handled 
and put in place, not liable to settle, etc. This has been accom- 
plished by making the material into compressed slabs or sheets to 
a density and stiffness sufficient to be easily handled, sawed and 
fitted same as if it were lumber. Slabs made of mineral wool 
are thus manufactured by two or three different firms in this 
country, and have the appearance shown in Fig. 6. These slabs 
are usually made in standard sizes of 18x48 inches and 36x48 
inches and from one-half to three inches in thickness, the manu- 
facturers being willing to cut these slabs to any size smaller 
than this, if specified. These slabs are a great improvement over 
mineral wool in bulk form, as they can be adapted to modern con- 
struction where it is the purpose to stratify or laminate the mate- 
rials to form a composite insulation, as such is now considered 
the most efficient in retarding heat transmission. 

Many methods of applying this "felt*' or mineral wool slab 
have been devised by the manufacturers, but these are more or 



less impraclicable on account of the assumption that these slabs 
are sufficiently strong to hold nails and support the construction ; 
and the fact that these boards are not air or moisture proof is 
overlooked and therefore the construction must make good these 
necessary requirements. Fig. 6 shows a method used by the 
author in applying this material. It will be noticed that the slabs 
are not necessary to the solidity of the construction, but they 
are placed between battens or furring and slightly tacked in 
place; waterproof paper is placed on each side and between each 
slab, thus preventing any leakage of air or moisture through the 
wall. Fig. 7 (see following page) shows a method recommended 

////////////////////^^^ COAT.NQ 

rtaoacvtai*;. ►x* ;«iz- 

— -^INCH D.1-M. D0ARD3 



by the manufacturer of applying mineral wool slabs to brick or 
stone walls in the construction of fireproof insulation. The wall 
is first coated with waterproof cement put on hot, into which 
the slabs or sheets of insulating material are set. Two or more 
courses of two or three inch slabs may be used, with the water- 
proof cement between. After setting the slabs, another coating 
of waterproof cement is applied and the surface plastered with 
Portland cement tioweled down to a smooth surface. If the 
mechanical difficulties of this method of applying may be over- 
come, the merits of this construction are apparent. 




Charcoal is described as a more or less impure form of 
carbon obtained from various vegetable and animal materials by 
their partial combustion out of contact with air. That most in 
general use is obtained from wood and is a hard and brittle black 
substance which in a granulated or flaked form is used to a 
large extent in England and in Europe for insulation. It is used 
as a filler and applied in the same manner as mineral wool or 


shavings. Charcoal has not been used to any considerable ex- 
tent in this country for insulation, except for the ordinary family 
refrigerator. Its use is not to be commended ; and on account 
of its black, dusty nature, it is very dirty, to say the least. The 
abundance of many other materials at hand, equally efficient, 
does not warrant giving it even a trial. 


Granulated cork is considered one of the most efficient and 
high-grade fillers for insulating purposes that we have, and it is 



odorless, clean, elastic, durable and does not absorb moisture 
readily, but like all other fillers, except mineral wool, is subject 
to attack by vermin, unless properly protected. It is well known 
that cork is the bark of a particular tree growing on the coasts 
of Northern Africa and Southern Europe. This bark is deprived 
of its non-elastic and impure substances, after which it is cut up 
into proper sizes for commercial use. The granulated cork is 
the waste product in the manufacture of stoppers, handles, etc. 


When filling spaces with the material, it should be rammed in 
tightly, so as to reduce the size of the air spaces between the 
particles, and to prevent future settling. Granulated cork mixed 
with hot pitch or asphalt has been used and is considered by the 
author to be a good insulator around brine mains where they 
pass through masonry walls or are laid under ground. With 
this material, molds or forms are placed around pipes and the 
mixture poured in hot, thus completely surrounding the pipes 
and making an indestructible covering. 



Cork has also been made up into compressed sheets, bricks, 
etc., of various sizes. The appearance of the sheets is shown 
in Fig. 8, and are usually made 12x36 inches in size and vary 
from one inch to three inches in thickness. These sheets are 
made by compressing the granulated material or shavings of cork 
in iron molds and baking in a temperature of about 500° F. 
This is done without the addition of any cement or binding ma- 
terial, but the process liquefies the natural gum of the cork 
sufficiently to bind the granules into a solid mass. In some 
processes a cementing material is used, making what are termed 
impregnated cork sheets. These boards are more or less porous, 

Inserted spruce nailing strip. 

Brick wall. 

Pitch, paint or paraflfine. 

Nonpareil sheet cork. 

Nonpareil sheet cork. 

{ Paper, if inside finish is wood. 
'( Paint, if inside finish is cement. 

Spruce sheathing or cement. 


and therefore to apply them practically the author has used them 
in constructions similar to mineral wool slabs, as shown in Fig. 
7, set between furring strips and with waterproof paper between 
each layer of sheet cork. 

The manufacturers evidently recognized the difficulty of 
applying the sheets (otherwise than shown in Fig. 7) without 
nailing through them. This was impracticable because the sheets 
lack sufficient strength to hold nails and nails are also objection- 
able on account of tearing the paper and cork. Consequently the 
two inch and three inch thicknesses of sheet cork can now be 
obtained with inserted nailing strips of wood, as shown in Fig. 
9. This is unquestionably a good improvement, as it gives a 



more solid construction for nailing, and does away with furring 
strips to some extent. Referring again to Fig. 9, the author 
would consider it impracticable and difficult to fasten the first 
sheet to the brick wall as shown. A better method would be to 
set horizontal nailing strips of wood in the brick wall every 
sixth or seventh course, or nail horizontal furring strips to the 
inside of the wall, set 18-inch centers and set the sheets ver- 
tically with joints lapped over the furring strips, as shown in 
Fig. 10. 

Another method of erecting cork sheets, which possesses 
several advantages, is to cement them solidly to brick or tile walls 



_^ -^ % INCH JXtn ©OARM 

viG. 10— ccx'S'er's method of applying sheet cork. 
in a bed of Portland cement. A single course of the cork sheets 
either two or three inches thick is used, or a double course with 
paper between, as shown in Fig. 8, according to the 
severity of the conditions. The interior finish may be 
either matched boards, which are nailed to the inserted wood 
strips in the cork sheets above referred to, as shown in Fig. 9, 
or a fireproof cement finish of either Portland cement or White 
Marble (Magnesian) cement may be applied directly to the ex- 
posed surface of the cork sheets, as shown in Fig. 8. This 
method gives an efficient insulation which is both waterproof 
and fireproof and is being used at present with very satisfactory 


As above stated compressed cork is made in shape and size 
resembling brick, which, for partitions and inside walls, are laid 
up in the same manner as brick with liquid or asphalt cement as 
a binder for the joints. Cork bricks are also made that are im- 
pregnated with hot asphalt or pitch so as to surround each par- 
ticle, the purpose being to produce an article that should be water- 
proof. This treatment would without doubt decrease the insu- 
lating value of the cork bricks and its purpose is therefore ques- 


Hair felt material has very appropriately been termed "Na- 
ture's Insulation," as there is no question but that nature created 


hair for the sole purpose of protecting life on this planet from 
the changes of temperature. It is one of the most indestructible 
materials with which we have to deal, and when properly ap- 
plied it is one of the best insulators available. Cattle hair as it 
comes from the tanners is thoroughly washed and air dried, put 
through pickers and blowers until all dirt, etc., is removed and 
the hair thoroughly deodorized. It is then put through felting 
machines where it is formed into sheets of one-quarter of an 
inch to two inches in thickness, put up in rolls twenty-four 
inches to seventy-two inches wide and fifty feet long. This felt 
has the appearance shown in Fig. ii. In specifying this mate- 


rial the author requires it to be furnished in narrow widths (pref- 
erably 24 inches) and applied between furring strips and paper 
set vertically as indicated in Figure 7. The sheets should run 
from floor to ceiling continuously and may be held in place by 
nails driven into side of furring strips at an angle and then bent 
in as shown in Fig. 12. No nails should be driven directly 
through the hair felt and papers, as that destroys the air and 
waterproof qualities to that extent and thereby decreases the 
value ot the insulation. In applying the sheets of hair felt to the 


viATERPuoor patch'' 


ceiling, it has a tendency to sag. This can be avoided by nailing 
temporary cross cleats to the furring strips every five or six feet, 
as the sheets of felt are put into place, and these can be removed 
as the inside wood finish is put on. If the hair felt is ordered in 
the proper width for use, there will be very little cutting to be 
done except to cut off the lengths as needed. The best method 
of cutting hair felt is with a long bladed sharp knife or chisel 
guided along a straight edge held down firmly; some workmen 
with accurate aim can do a fair job with a sharp hand axe. 

Besides being used as it comes from the manufacturer, hair 
felt is put up in many ways by applying paper, etc., to the sur- 
face. At present it may be obtained with a waterproof paper on 
one side put on with a waterproof glue. In some situations this 
would be very desirable. 


Those insulating materials known as "quilts" are in the na- 
ture of a felt held in place betw^een two papers and stitched to- 
gether, and are usually made in one-quarter and one-half inch 
thicknesses, thirty-six inches wide, put up in rolls of from 100 
to 500 square feet. These quilts were originally designeJ and 



manufactured for deafening purposes, viz. : to absorb and dissi- 
pate the sound waves penetrating through floors and partitions 
in dweUings, etc., where with proper construction they serve 
both as deafeners and insulators. 

There are various filling materials used for making up these 
quilts, such as hair felt, mineral wool, flax fibre and eel-grass, 
all of which are very durable, each possessing qualities that 
recommend them for use. The nature of the hair felt and 
mineral wool has already been touched upon. The so-called flax 
fibre, recently introduced, is made from flax straw, that has 
been crushed, picked and deodorized, and the sap or gum re- 
moved, leaving a light fibrous material that if properly protected 
makes a good insulator. Eel-grass is used in "Cabot's Quilt" 


exclusively and has been on the market for a number of years as 
a deafening material. The quilt has the appearance shown in 
Fig. 13. This eel-grass, or sea weed, as it is often called, is a 
long, grass-like material of great durability.* It has great re- 
sistance to fire, and owing to the large percentage of iodine 
(common to all sea-plants) which it contains, it is repellant to 
rats and vermin. 

For the application of these quilts to cold storage and re- 
frigerator car construction, they have been made in thicknesses 
up to one-half inch, and waterproof papers have been placed on 
one or both sides of the quilt instead of the common building 
papers. Some makers have coated one side of the quilt with a 
waterproof asphalt coating, this to be turned toward the damp 
side of the wall. These improvements have enhanced the value 
of these quilts for insulating purposes and they compare very 
favorably with other materials for practical use. 

• "A sample of eel-grass, 250 vears old and in a perfect state of preservation, may 
be seen at Mr. Cabot's office." — F. E. Kidder in "Building Construction." 



The common method of applying is to place a layer of quilt 
between two sheathings of flooring and nail through it, and then 
apply more sheathings and quilt as shown in Fig. 14. While 
fair results can be obtained by this construction, it is somewhat 
impracticable on account of the elastic nature of the quilt, and is 
also wasteful of lumber. A better method of applying these 
quilts and saving lumber and increasing the insulating value 


would be as recommended by the author and shown in Fig. 15, 
on following page. In case it is desired to omit the shavings, the 
wall may be furred with %-inch strips and the quilt then applied, 
as shown, to the number of thicknesses desired. 


As already stated, the very nature of insulating materials 
or fillers is their porosity, and therefore air under even a light 



pressure will flow through them quite easily. To prevent this 
flow of air and the penetration of moisture is absolutely neces- 
sary, otherwise the insulation will become damp, and in time al- 
most worthless on account of deterioration and decay. It is the 
general practice to use air-tight and waterproof papers on each 
side of the insulating materials for the purpose of preventing 
this flow of air and moisture through the walls. 


There has been a widespread impression that papers possess 
a high insulating value, and consequently many expensive and 
complicated insulations have been constructed, using paper as 
the chief material. It is now generally recognized by refriger- 
atmg engineers that although paper has some insulating quali- 
ties, its chief value is in its resistance to the passage of moisture 
and direct flow of air through the walls. Its use- also tends to 
make an msulated wall more composite without increasing its 


thickness, as it changes the density of the insulation and thereby 
retards the transmission of heat. Besides the requirements of 
being air and water proof, papers must be odorless, having 
strength and durability, and should not be brittle and liable to 
crack in low temperatures, as this makes them difficult to handle 
and results in leaky insulation. 

There are a great many insulating papers on the market, 
some of which are reliable and durable, but all rosin-sized, oiled 
and tar coated or tar saturated papers should be avoided on ac- 
count of their odor, and the rosin-sized papers also avoided on 
account of the positive certainty of disintegration, because they 
carry their own destructive elements. It is also advisable to 
avoid all so-called ''coated" papers, that are coated on both sides 
and have a white center, as they will disintegrate sooner or later, 
if unfavorable conditions arise. Papers should be selected that 
have been saturated and thoroughly impregnated with pure as- 
phalt or similar material or have a center layer of asphalt, as 
thus they are practically indestructible when used for cold storage 
Insulation; these qualities, combined with the requirements above 
stated, make them superior to all others for insulating purposes. 
These high grade papers are more expensive in first cost, but 
their durability makes them cheaper in the end. As the cost of 
using good papers is usually less than 5% of the total cost of 
the insulation, it is poor economy to select an inferior grade. 
Insulating papers are usually manufactured thirty-six inches wide 
and come in rolls of 500 or 1,000 square feet. 

The papers should be applied with the greatest care in lap- 
ping around corners, etc., all joints should be lapped at least two 
inches and under severe conditions these joints should be ce- 
mented. It should be kept in mind that the proper application 
of the papers is one of the most important parts of the insulating 
work, because, as already noted, the insulation must be air and 
water proof to remain efficient for any length of time. If the 
workmanship is poor, the advantages of using first-class papers 
are neutralized. 


Wood has, of course, played as important a part in construct- 
ing insulation as it has in general building operations, because of 
the ease with which it can be procured and worked, together with 


its strength, lightness and durability. In addition to its general 
use for floor construction in brick warehouses (except in thor- 
oughly fireproof structures), it is used for forming the air spaces 
or filled spaces and inside finish of the insulated rooms. Wood 
has been regarded as a good insulator, and this belief has, in 
many cases, tended to its excessive use in constructing insula- 
tions, such as, for instance, the use of from six to ten thicknesses 
of boards in one wall. Considering the greater insulating values 
of fillers over solid wood, it is becoming the general opinion of 
most refrigerating engineers that many thicknesses of boards 
built up with air spaces in such a manner, is not only extremely 
expensive, but it is not efficient as an insulator in proportion to 
the cost and space occupied. One of the chief requirements in 
the use of wood, already stated as essential to other insulating 
materials, is that it should be odorless. This applies particularly 
to the inside sheathing and finish. This requirement restricts the 
kind of woods available to a very few, of which spruce, fremlock, 
basswood and whitewocd are the most desirable. Spruce is to 
be preferred on account of being easier to work and not so liable 
to have loose knots and shakes as hemlock, but it cannot be easily 
obtained at reasonable prices in large quantities except in the 
eastern states and the far west. Hemlock is abundant in all the 
northern, middle and eastern states, where it is used extensively 
in all building operations, but it is cross-grained, rough and 
splintery, and very prone to split when nails are driven into it. 
It is stated that owing to its splintery nature, hemlock is prac- 
tically mice and rat proof. White pine may sometimes be used, 
when the other kinds are not available, but it should be as free 
as possible from rosin and thoroughly seasoned. For a ware- 
house in Butte, Mont., designed by the author, it was necessary 
to use tamarack for the inside finish as the only native wood 
available that did not have a strong odor, and its use in this case 
was very satisfactory. Where it is necessary to use a wood that 
may have a slight odor, it should be given one or two coats of 
properly prepared whitewash or other deodorizer as soon as the 
walls are finished. 

That lumber should be thoroughly dry to get the best results 
in efficiency and durabilitv of the insulation it is almost unneces- 
sary to state. If the lumber is even partially green, it carries a 


considerable amount of moisture with it into the insulation, caus- 
ing more or less injury. The use of under-seasoned lumber 
should be properly guarded against. In erecting insulation dur- 
ing cold weather it is very necessary to keep fires going so as to 
have all materials as dry as possible. This is often neglected. 

All boards for sheathing should preferably be dressed and 
matched, as it gives more air-tight work, and particularly for 
inside finish, as it has a much better appearance. Rough board- 
ing may often be used for the interior of the insulated walls 
where the joints are properly protected, and rough boarding has 
often been used for inside finish solely for the purpose of giving 
a rough surface for whitewashing, as it is claimed that whitewash 
will peel or flake off of a dressed wall. This is, however, not 
considered a valid reason by the author, as whitewash properly 
prepared will not peel oflf. (See chapter on "Keeping Cold Stores 


The use of any particular kind of nail may, on first thought, 
seem to be of little importance, but when we considef that the 
efficiency of the completed work depends upon every detail of 
construction and that nails are good conductors of heat, there is 
no question that the kind of nails and the manner of their use 
is of some importance. The author usually specifies that "cement 
coated wire box nails" be used. These nails have a smaller diam- 
eter than the ordinary wire nails, but the cement coating gives 
them greater holding power. This fact permits the use of a 
smaller size nail for the same class of work, for instance : where 
8d and lod common nails are used for sheathing, 6d and 8d 
cement coated may be used for the same work. It is therefore 
evident that using cement-coated nails not only reduces the heat 
transmission on account of their smaller diameter, but also on 
account of being able to use nails one-half inch shorter, as indi- 
cated above. The cement coating also protects the nails from 


Strictly speaking, all constructions are composite (except 
solid wood or masonry construction), as they are necessarily 
made up of materials having different densities and different 



values as insulators. An English authority divides insulated 
walls into two classes, which he calls the "forced" and "optional** 
insulation. The former is of course the masonry wall of the 
building proper, and the latter the "lining'' or material added 
as insulation. Where the building is a frame structure, as is 
often the case, the whole wall may be termed optional insulation, 
because the space between the studding of walls may be insulated 
with any filling material desired. 

As already stated, even if the insulating value of one inch or 
one foot in thickness of this or that material be known, it gives 
no practical basis on which to design insulations, except as a 
guide as to what materials may be used. To calculate the value 


of composite insulations by the use of formulae is extremely inac- 
curate, as account should be taken of the papers used which have 
more or less value. It is for the purpose of determining the 
value of composite insulations that various testing apparatus have 
been designed by diflferent experimenters. It may not be out of 
place to describe these briefly, so as to be able to judge the relia- 
bility of the results obtained in the diflferent cases. 


The most common and inexpensive apparatus used is a box 
constructed of the material that is to be tested and provided in- 
side with a watertight tin box having a drain pipe with a trap 


connected at the bottom, similar to that shown in Fig. i6. Top 
of box is provided with a removable tight cover. This complete 
box is then placed in a room where a constant temperature is 
maintained and a known quantity of ice is placed inside the box. 
At stated intervals the ice meltage can be determined by weigh- 
ing the water coming from the ice through the drain pipe in bot- 
tom. To get comparative results boxes made of various mate- 
rials, but of the same size and thickness, can be fitted up and all 
tested under the same conditions. The quantities of ice melted 
in each case can be ccwnpared and the relative efficiency of each 
material judged. 

To determine the rate of heat transmission in B. T. units 
for this kind of tester, it will be necessary to consider time, dif- 
ference of temperature, square feet of surface in box and ice 
melted. This can be illustrated by an imaginary test case as 
follows : Take a tester two foot cube inside measurements with 
walls four inches thick, the inside and outside temperatures being 
respectively 32° F. and 70° F. (assuming the inside temperature 
to be the same as the ice) and the meltage of ice per day (24 
hours) is 50 pounds, we then have: 

Inside surface 24 sq. ft. 

Outside surface 42.6 sq. ft. 


Mean surface between inside and outside of box 33.3 sq. ft. 

Difference of temperature between inside and outside of box 38° F. 

Ice melted per day (24 hours) 50 lbs. 

142x50 equals B. T. U. transmitted per day =7100 

B. T. U. transmitted per sq. ft. per day y 

B. T. U. transmitted per sq. ft. per hour per deg. difference . -j -r^ ' -= 0.233 

Testers similar to the one above described with changes in 
details, spaces provided for thermometers, etc., have been de- 
signed with the purpose of getting more accurate results, if pos- 
sible. Riege and Parker* designed and used a tester which they 
described as follows: 

In testing the value of insulating walls or partitions there should be 
some means of determining accurately the rate of flow of the heat through 
the wall or partition. This can be done with accuracy in several different 
ways, though in the following test the apparatus used consisted essentially 

• Ice and Refrigeration, January, 1895. 



of a wooden box, a tin 1>ox, thermometers, and a pail to catch the drip 
from the ice, the agent used in cooling. The boxes were respectively 
forty-four inches and twenty-five inches cube on the inside, the tin box 
containing the ice to be melted. The wooden box was made of %-inch 
white pine tongue-and-groove boards, nine inches wide, and really was 
a double box, the boards of the inner one running at right angles to 
those of the outer in order to make the box as air-tight as possible. The 
lid of the box, which was twelve inches deep on the inside, had a 12-inch 
band around the edge where the lid rested on the box, and to make the 
joinings of the two as air-tight as possible, the edge was lined with felt. 
Both the lid and the box were then lined with what is known as builder's 
paper or "sheathing," which secured a still better protection against out- 
side changes of temperature. The tin box rested on a couple of wooden 
horses, twelve inches high, so that when placed in position, there was a 
space of twelve inches all around the tin to the sheathing. From the 
bottom of the tin box led a tube which passed into an inch pipe, this 
latter pipe extending through the wooden box, and the lower end being 
immersed in a can of water, prevented any outside air from entering either 
box. All fittings were air-tight. Thermometer tubes were let in from the 
four sides to within six inches of the tin box, as well as a long tube from 
the wooden box cover through the tin box cover to within a couple of 
inches of the ice. 

Before starting a test the ice was allowed to melt until the drip from 
the can showed a regular flow, thereby allowing the true weight of ice 
melted during the test to be determined. During a test temperatures were 
noted on all four sides of the wooden box, also within six inches of the 
tin box, and also inside the latter, the readings being taken half hourly 
and the weight of ice melted hourly. When the thermometer tubes were 
not in use, they were closed with corks. Comparison tests were made of 
each substance, each test lasting from six to twenty-four hours. Tests 
were made of air, shavings and cork, first at ordinary temperature and 
later with a steam coil an inch above the wooden box to represent the 
effect, when steam was circulated, of the sun on the roof of a storage house. 

A later improvement on the above described tester, which is 
used by some experimenters to-day, where simplicity and cost 
must be considered, is to construct it similar to a domestic refrig- 
erator, and about the same size, with an ice bunker and air ducts 
installed so as to get a uniform circulation and temperature in- 
side. Small windows with three or more thicknesses of glass are 
placed in sides of testers to read the thermometers which are 
hung inside. The heat transmission is calculated in the same 
manner as described for small tester above. 

The comparative results that can be obtained with the above 
described testers are quite accurate when the different materials 
tested are of the same thickness in each case. But in comparing 
different thicknesses of material, there is a chance for great error 
unless the inside dimensions of tester are changed so as to give 
the same proportionate mean surface. This fact is readily seen 
if the tester shown in Fig. 16 is taken and the walls made eight 


inches thick instead of four inches. The mean surface. of the 
tester in that case would be 45.3 square feet, as against 33.3 
square feet in the first case. This difference in mean surface 
would favor the thicker insulation w^hen calculated in B. T. U. 
John E. Starr, in an article on *' Non-conductors of Heat,"* 
describes the testing apparatus he designed and used at that time, 
which was quite complicated as compared with those above de- 
scribed, but was no doubt intended for greater ranges of tempera- 
ture than could be obtained with them. He describes his tester 
as follows : 

The writer, in investigating the value of insulating construction, has 
used a rather simple but effective apparatus for accurately measuring the 
flow of heat. He has a box carefully constructed and thoroughly insu- 
lated on the top, bottom and two sides. The two ends remaining (expos- 
ing an area of something over four square feet) were used as the test 
ends, and the various styles of construction to be tested were built in these 
ends. In this way two tests could be made at the same time. Directly 
against these two ends were placed water reservoirs of thin galvanized 
iron of the same superficial area as the test ends, that is to say, something 
over four feet square. These reservoirs were about one inch wide and 
each held from twenty-five to twenty-seven pounds of water. Outside 
of these reservoirs was another very thick insulation against the outer air, 
all except a small opening in the middle of the top for thermometer 
readings. A steam coil was placed inside of the box, and connected at 
its inlet with a steam boiler and at its outlet with a steam trap. By regu- 
lating the steam pressure the interior of the box can be kept at any desired 
temperature; and the construction is such that any heat that finds its 
way into the water must come through the insulation to be tested, and 
that all the heat that comes through the insulation must find its way into 
the water, as the water exactly covers the insulation. The tests, there- 
fore, can be made quantitative, as well as qualitative, by observing the 
rise of temperature of the water, and taking into account its weight. 
Readings are taken at regular periods of the temperature inside the box, 
and of the water in each cap, or reservoir, and of the surrounding atmos- 
phere. The water caps, however, are so thoroughly insulated from the sur- 
rounding atmosphere that unless the temperature of the water in the 
caps rises to a very high degree, and unless the test is of very long dura- 
tion, only a small amount of heat escapes from the water and passes 
into the air. The value of the insulation surrounding . the caps being 
known, however, a correction can be made, if necessary, for such escape 
of heat from the water. 

What is probably the most valuable and scientifically accu- 
rate testing apparatus in use was constructed by the Nonpareil 
Cork Manufacturing Co. at their factory at Bridgeport, Conn. 
A description of this apparatus was published in Ice mid Refrig- 
eratiati, June, 1899, and is reproduced here as follows: 

Their apparatus consists of an insulated room. 12x10x8 feet, the tem- 
perature of which can be held at any point desired from zero Fahrenheit 

* Ice and Refrigeration, July, 1891. 


up, by means of a W. M. Wood compression machine operating with 
direct expansion. A uniform temperature throughout the room is secured 
by forced circulation, an electric fan being used to drive the air up over the 
expansion coils which are inclosed at one end of the room. The air 
passes out and down through a false ceiling having graduated perfora- 
tions arranged to allow a uniform amount of cold air to fall in all parts 
of the room. This is the method employed in various refrigerating plants 
with entire success, by Mr. John E. Starr. In the center of the room is 
an insulated box, 3x3x6 feet inside measurement, having one side remov- 
able. It contains an electric heating coil and a small electric fan arranged 
to give a circulation of air and insure uniform temperature in all parts 
of the box. Standard thermometers, both mercurial and recording air 
pressure, reading i/io^ F., are placed so as to give the temperature of the 
refrigerated room and the heated box, the readings being taken outside 
the room. This obviates any necessity of the operator entering the refrig- 
erated chamber while the test is being made. The Weston standard 
ammeter and voltmeter measure the electricity supplied in the fans and 
heating coil, and a suitable rheostat regulates the amount of the current. 

The method of determining the heat conductivity of any in- 
sulating construction is as follows : 

The temperature of the room and box are respectively lowered and 
raised until they conform to the conditions under which the proposed 
insulation will be used. Then the amount of heat or electricity supplied 
to the box is gradually diminished by means of the rheostat, until the 
point is reached where the temperature in the box remains constant. It 
is evident that at this point the radiation must exactly equal the amount 
of heat supplied, or there would be a rise or fall in temperature, as the 
case might be. After the supply and radiation have been maintained con- 
stant for two hours, readings are taken every five minutes for three hours 
more. If they do not vary more than i/io of i°F., they are considered 
practically exact. The average is taken as the permanent radiation of the 
box under the given conditions. The box contains 100 square feet of 
surface, measured at the center of insulation, consequently i/ioo of the 
total radiation is the rate per square foot. This rate being obtained, the 
removable side of the box is replaced with a side constructed of the 
insulation whose value is desired. The test is then repeated, and the 
total heat loss from the changed box will be greater or less, as the case 
may be. The removable side contains twenty square feet surface, there- 
fore eighty square feet of the box remain unchanged, and the radiation 
through this must be the same as before. This amount is at once deter- 
mined from the previous tests, and the difference between the total heat 
loss from the box in its changed condition, and this amount must give 
the radiation through the twenty square feet, comprising the new side 
which has been put in. One-twentieth of this amount is of necessity the 
rate per square foot, and this divided by the difference in temperature 
between the room and box, will give the exact radiation per square foot 
of surface per degree of difference in temperature. 

A testing apparatus which has been used by the author is 
based on the same principles as that above described, but some- 
what smaller in size and of simpler construction. The tester was 
built with one side removable and arranged so that any kind of 
insulating material could be tested in same. This tester was 



placed in a €old storage room where a temperature of 15° F. 
could be obtained and which was equipped with an air circulating 
system. The inside of the tester was heated by eight incandes- 
cent electric lamps, each controlled by a button switch from the 




FIG. 17. — cooper's insulation TESTING APPARATUS. 

outside. The temperatures inside of the tester were observed by 
means of a specially made long-stem thermometer projecting 
through top of tester and read from the outside. The ther- 
mometer was graduated to read to 1/5 of a degree. The appa- 
ratus is shown in Fig. 17. 


The incandescent lamps used were no and 52 volts of 16 
c.p. on a S2-volt circuit. These would give approximately 50 
K. T. units and 200 B. T. units respectively per hour, but they 
were accurately calibrated by a water calorimeter test. This con- 
sisted of an insulated tank, capable of holding twenty-five or 
more pounds of water, which was allowed to stand in a constant 
temperature until the temperatures of the water and tank were 
equal. Under such conditions each lamp was put in a water- 
proof socket and tested separately by immersing in the water and 
noting time taken to raise twenty-five pounds of water 1° F. In 
this way the B. T. units of each lamp per hour were obtained, 
and with each lamp controlled separately, the temperatures in 
tester were controlled at will up to 150° F. Owing to the fact that 
the life of incandescent lamps is limited, they will, after a certain 
time, decrease in power. This made it necessary to retest them 
periodically. The author believes that the results obtained with 
the above apparatus are as accurate as those that have been ob- 
tained by other experimenters. 


The results obtained by the different experimenters have 
been illustrated and published in various trade papers, pamphlets 
and catalogues. The author has assembled and illustrated these 
results in the following figures as accurately as information per- 
mits. Figs. 18 and 19 give the result of tests made by John E. 
Starr (some of which were made by the Nonpareil Cork Mfg. 
Co.), at different times and for different purposes. Most of 
these were presented by him in a paper read before the eleventh 
annual convention of the American Warehousemen's Association 
in October, 1901.* 

Figs. 20 and 21 give the results of other tests made by the 
Nonpareil Cork Manufacturing Co. with their elaborate testing 
apparatus, described above, comparing their material, for the 
most part, with the wood board and air space construction. 

Fig. 22 is a reproduction from an article in Ice mid Refrig- 
eration, September, 1896, on "Cold Storage Buildings." The 
drawings are there credited to the Fred W. Wolf Co., who give 
the heat transmission as having been determined from practical 

• Reported in Ice and Refrigeration, November, 1901. 


experience, but do not describe how or by whom these tests were 

Fig. 23 gives the result of tests made by the author with 
the testing apparatus above described as designed by him. These 
show the tests on a variety of materials and were not made in 
the interests of any of them in particular, but were made chiefly 
to determine the value of air space construction as compared with 
filled spaces and sheet material. 

The above described tests are all based upon the amount of 
heat transmitted per square foot, per degree of difference between 
inside and outside temperatures, per day (24 hours). 

. Figs. 24 to 28 are reproductions from drawings made by 
George H. Stoddard and accompanying his paper on "Insula- 
tion," which was read before the eleventh annual convention of 
the American Warehousemen's Association.* The nature and 
form of testing apparatus which was used to obtain the results 
shown in these drawings was not given by him in his paper. In 
explanation of these drawings we quote in part from his paper 
as follows: 

It may be of interest to consider how the transmission of heat takes 
place through an outside wall, such as is often used for a cold storage 
warehouse. _ Fig. 24 shows a section of such a wall. Starting from the 
outside, it is made up as follows : 24 inches of brick, 2-inch air space, 
two ^-inch matched spruce sheathing with paper between, then twelve 
inches of spruce mill shavings, then two ^-inch spruce sheathing, with 
paper between. We will assume a temperature of 92° F. for the air and 
objects outside, and a temperature of 32° F. for the air and objects inside 
of the warehouse. Heat is transmitted through this compound wall as 
follows: To the outer surface of the brick by radiation and contact of 
air, through the brick by conduction, across the air spaces by radiation 
and contact of air, through the inner wall of sheathing and shavings by 
conduction, and from the inner surface of the wall by radiation and 
contact of air. 

Knowing that the rate of transmission must be the same to and 
through and from the wall, it is of interest to note the temperatures of 
the different faces of the wall, and see how they vary from the outside 
temperature of 92°, to the inside temperature of 32°. There is only the 
difference between 92° arid 90.7° between the outer air and the outer 
surface of the wall, then the temperature drops to 81.8° at the inner 
surface of the brick, to 80.1** at the other side of the air space, to 76° 
at the inner surface of the outer double sheathing, to 37.4'' after passing 
the Savings, to 33.3° at the inner surface of the inner sheathing, and 
then to the temperature of 32° in the room. 

In Fig. 25 are shown curves representing the rate of transmission 
through walls similar to that which we have just considered, with the 
brick wall varying from eight to twenty-eight inches in thickness, com- 
bined with inner walls having the shavings from two to twelve inches 

• Published in Ice and Refrigeration, November, 1901. 

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FIG. 25.— I 

Stoddard's diagram showing rate of heat transmission through 

FiG 25a. — Stoddard's diagram showing construction of above wall. 



jof*^^*^ ynoi^^^d looj j^vno? "^'' qjiiiuqnv^i '••niQ 



thick. The vertical distances in all of the similar diagrams represent the 
B. T. U. transmitted per square foot per hour per i° F. difference in 
temperature between the inside and outside of the wall, and also the 
equivalent pounds of ice melted per square foot per twenty-four hours 
for a difference of a little over 59° F. 

Fig. 26 shows a similar curve for a partition of typical construction 
(see Fig. 27), with the thickness of shavings varying from two to 
twenty-four inches. 



ICE --07Z2> 

B .T.U. -.0587 B.T.U.=.076 

ICE =0587 ICC = 0.76 



In Fig. 27 are shown partitions made up of sheathing and with one, 
two, three and four air spaces, and also one made up of sheathing and 
paper with nine air spaces, and the rate of transmission of heat through 
such insulation is given in B. T. U. and ice melted. In Fig. 28 is given 
the actual thickness of different partitions packed with various insulating 
materials of such a thickness that all of the complete partitions shall be 
of the same insulating value. There is also shown one made up of 
sheathing with air spaces. From this is seen how much more space is 
taken up by one form of insulation than by another. 



An examination of Figs. 27 and 28 will show the comparatively 
small value of air spaces for the purpose of insulation, and it may be 
stated, that, for this purpose, a wide air space has no greater value than 
a narrow one, and that any space over one-half inch in width, if it can be 






B.T.U = .0+83 
ICE = 483 

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kept dry, will be of greater value if filled with an insulating material as 
good as mill shavings, than if left as an air space. 


It is evident from the results shown with the various con- 
structions, that those built up out of wood boarding and air 
spaces, or air spaces formed with battens and paper make the 
poorest showing when the space occupied and cost in labor is 
taken into consideration. The author considered the one-half 
inch air spaces formed by battens and paper as shown in his tests 
to be efficient until practical experience and the tests conducted 
by him proved otherwise. The workmanship in building such 
spaces is usually poor, as unusual care, not appreciated by the 
average workman, must be taken so as not to puncture them 
when under construction. Air space construction is difficult to 
erect so as to be air and moisture proof. 

Another extensive use of air spaces has been between the 
brick wall and the insulation, as shown in Figs. 25 and 29. The 
alleged purpose of its use at this ■ point has been, first, proof 
against moisture entering the insulation; second, for the insulat- 
ing value it may have. With the growing disbelief in the use 
of air space construction, this second purpose can be considered 
of little value. The prevention of moisture entefing the insula- 
tion from brick walls by the use of air spaces is only partially 
true, as may be readily understood. The moisture will enter the 
air space and will eventually aflFect the insulation more or less. 
There are sometimes local conditions that would warrant the use 
of an air space between the brick wall and insulation, but in the 
opinion of the author, such design should be avoided wherever 
possible by waterproofing the brick wall and placing the insula- 
tion against the waterproofing. This method saves both space 
and material for the same insulating efficiency obtained. The 
question of the amount of space occupied by the insulation is of 
much importance, as it represents a certain money value, both 
in first cost and as storage space, and it should be the designer's 
aim, within practical limits, to use the best insulation and that 
requiring the least space. 


Fig 30 illustrates a construction used to a great extent by 
the author in his cold storage work. The inside of the masonry 



'jECTtCK or lr^*uL,^Ttc»J- 

: Li lii ii nor 

I Li — < 

Plan or Insulation- 

FIG. 30. — cooper's design FOR INSULATED CONSTRUCTION. 





f '-TfelfHCH IXin. BOARDS 


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/// /[' //riLLCD WITH 5HAV1N03 






walls are waterproofed and the filled space of from six inches 
to ten inches is placed against it, then the sheathing, sheet ma- 
terial and papers are placed inside, next to the storage rooms. 
With an eight-inch filled space and four-inch sheathing and 
sheet material as shown, a total of twelve inches, we have an 
insulation for a storage temperature of 30° F., and the basement 
with a total of thirteen inches, for a temperature of from 20"^ 
to 25° F. For sharp freezing purposes there should be a ten-inch 
filled space and an additional thickness of sheet material. 

Fig. 31 illustrates the construction and insulation of a frame 
building suitable for a temperature of 30° F. The space between 
the studs should be subdivided, as shown in plan Fig. 31 -a. This 
lessens the liability of settling of the filler and the penetration of 
moisture. The use of wide filled spaces such as shown in Fig. 24 
is not considered good practice, as heat passes through a construc- 
tion of uniform density more rapidly than through one made up 
of successive layers of diflPerent densities, therefore the thickness 
of the wall in the former case will be greater than that in the 
latter to obtain the same insulating value. This is evident by 
referring to Figs. 24 and 30, the former with twelve-inch brick 
waH, air space and twelve-inch shavings, as shown, a total of 
thirty inches in flTTckness, transmitting ^ B. T. U. per square 
foot per day per degree difference between inside and outside 


temperature. The latter, with twelve-inch brick wall, eight-inch 
shavings and five inches of sheathing, sheet material and paper, 
as shown, total twenty-five inches in thickness, will transmit same 
amount of heat. Here is a saving of five inches in storage space 
which will earn the difference in- cost between the two construc- 
tions in a short time. 

Another feature in the construction shown in Fig. 30 of 
equal importance to the space saved, is durability. This is accom- 
plished by placing the indestructible materials, such as water- 
proof paper, and mineral wool block, sheet cork or hair felt in 
successive layers on the side next to the storage room where the 
conditions are most severe. These severe conditions are caused 
by a tendency of the enmeshed air in all insulating materials to 
condense the moisture held in suspension when subjected to low 
temperatures. This moisture will impair the durability of some 
materials, such as sawdust, shavings, etc. That such condensa- 
tion does take place within the insulation, near the low tempera- 
ture side, was demonstrated to the author in the tests made by 
him. Between each test the removable cover was unscrewed 
from the tester, which was located in the cold storage room, and 
taken into a room having an ordinary temperature, where the 
material in the cover was changed for the next test. The en- 
meshed air in the material put into the tester, was of an ordinary 
temperature and held a certain proportion of moisture in sus- 
pension, and when the material was reduced to the low tempera- 
ture in the cold storage room, this moisture would condense on 
the cold side of the layer confined by the waterproof paper. In 
some cases where the room temperatures were ver}- low the con- 
densed moisture would freeze on the cold side. These conditions 
obtained, depending on the dryness of the material when it was 
put into the tester, but would show more 6r less moisture m 
almost every case. The moisture condensed would be greatest 
in the layer nearest the cold side of the partition and would grad- 
ually diminish in each layer toward the high temperature side, 
where it would be perfectly dry. This was not moisture that had 
been carried into the insulation by the leakage of air, but was the 
condensation of the moisture held in suspension by the air en- 
meshed in the material. Air space construction showed the great- 
est condensation, wide filled spaces came next and the high grade 


of sheet materials divided by waterproof paper showed the least. 
From the above it is evident that high-grade materials should* 
be used next to the storage rooms, as they will not deteriorate 
as rapidly with the presence of moisture. This construction also 
protects the loose filler in the filled space, which is removed fur- 
ther from the inside wall, therefore making its duty less severe 
as regards the action of moisture. This construction is shown in 
Fig. 30, as used by the author. It is also evident from the above 
described action of m.oisture in the insulation, that the importance 
of using dry materials cannot be urged too strongly, and this 
fact has probably as much to do with durability and efficiency of 
the insulation as the nature of the material used. 

Where the storage space occupies two or more stories, it 
has frequently been the practice to insulate the intermediate floors 
out to the masonry walls and then erect the wall insulation inde- 
pendently for each story, as shown in Fig. 29. This is a ques- 
tionable practice, as it increases the number of joints in the con- 
struction and consequently the chance of air leakage into the 
rooms. Cases illustrating the damage from air leakage between 
joints and above ceiling or beneath floors of storage rooms come 
to the author's attention frequently. The last one was so pro- 
nounced a case that the entire ceiling of an upper room became 
so rotten in a few years' time that it practically fell, making the 
entire renewal necessary. The damage was caused by leakage of 
air, and consequent deposit of moisture on the cold ceiling. 
Whe«-e the building is a fireproof structure with steel beams 
and masonry floors, it cannot of course be insulated otherwise 
than by treating each floor independently, or in a similar way 
to that shown in Fig. 38. 

A better method than that shown in Fig. 29 would be to 
carry the wall instflation continuous from floor of lower story 
to ceiling of upper story, as shown in Fig. 30. Where the ends 
of joists l>ear into the w^all, the insulation should be scribed and 
closely fitted around each joist. This is easily done where the 
construction is properly designed to allow a wide spacing of the 
joists. Insulation constructed in this way decreases the chances 
of leakage to the minimum. 

Referring again to Fig. 29, it will be noticed that the spaces 
between joists are but partially filled with the filling material, 




leaving an empty space in each case. This would have been of 
greater insulating value if packed full to the top. The spaces 
between the lower floor joists should first have been lined with 
waterproof paper before the filler was put in, as shown in Fig» 
31, to prevent the penetration of air and moisture. 

The insulation detail for a steel ice freezing tank, as shown 
in Fig. 32, is of the general form used by most designers. At- 
tention is here again called to the use of the high-grade insu- 
lators at what will be the coldest point of the insulation for the 
reasons already discussed. In the light of our present informa- 

VtA'STV Da. - S**CCN. 
I'snuCC ^U.LCt^ with pttch- 
TbiNcn u^M &a*H&3 



tion, the use of a 2-inch or 4-inch air space next to the steel 
tank would be considered a waste of space. This would much 
better be filled with granulated cork and hot pitch or asphalt, 
as shown in detail, as this would prevent the condensation of 
moisture and protect the steel tank from corrosion. The space 
under bottom of tank should first be filled level with top of floor 
cleats and then the tank set in place, after which the space 
around sides can be poured full from the top. A frequently neg- 
lected detail is covering the top edge of tank insulation with 
galvanized iron or other waterproof material, as shown in Fig. 
32. This detail should not be overlooked or slighted, as the 


unavoidable spilling of water and dripping of brine in connection 
with ice making will eventually damage the insulation. 


The tendency of modern building construction, especially in 
our large cities, is toward the solution of the problem of fire- 
proofing, so as to decrease the danger and risk of fire. It is 
natural that this same problem should confront the cold storage 
man, but the difficulties of providing insulation that would be 
fireproof, and remain at the same time insulation in fact, is a 
problem not easily solved. 

In the article on "Insulation for Cold Storage," read before 
the eleventh annual convention of the American Warehousemen's 
Association, Starr stated regarding fireproof insulation, as fol- 
lows : 

I cannot refrain from alluding to the subject of fireproof insulation, 
more in the hope of drawing out information than adding to it. Steel 
frame work has in the past been a considerable bugbear to cold storage 
men, but the time is already at hand when the problem of entirely fire- 
proof construction, both as to building and insulation, must be solved. 
As to the insulation end of the problem, the difficulty is not so much with 
the question of obtaining a fireproof filling material, but to find a sub- 
stitute for wood, to hold the material in position. Cementing insulating 
material in the shape of blocks has been experimented with, but if the 
cementation is enough to give Sufficient ruggedness to the block the insula- 
tion qualities are, as a rule, impaired, and the cost as well as the space 
occupied by the insulation is increased. 

If a semi-fireproof insulation that might be classed as fire-retardant 
construction is permissible, the problem is somewhat simpler, as several 
materials are at hand that can be classed as retardants, such as compressed 
cork, hair felt, silicated paper, air spaces, etc., but if the whole structure, 
studs, filling material and wearing face, are to be fireproof, we are practi- 
cally restricted to mineral wool, mica and calcined pumice for filling 
material; and for retaining and wearing wall, to brick or some of the 
various cement fireproof boards on the market. The use of the latter 
would seem somewhat experimental, and the question of fireproof studs 
for supporting them, so far as I know, has not been answered. 

As nearly all building materials available that can be called 
fireproof are poor insulators against heat, it is evident that the 
walls must be extremely thick to have the same insulating value, 
or the machinery must take up the extra heat transmitted through 
them. The former course, with the present method of construct- 
ing fireproofing, is almost prohibitive on account of first cost and 
the space occupied; the second course necessitates a continuous 
heavy operating expense. The advisability of fireproof insula- 
tion, especially in small houses, is questionable, as the items of 


interest on investment, space lost, and increased operating ex- 
penses will oftentimes equal the difference in insurance rates ob- 
tained between a fireproof and a well designed "mill constructed" 

It is the observation of the author that the greatest number 
of fires occurring in cold storage warehouses originate outside of 
the storage rooms, except in occasional instances where it is 
caused by defective electric wiring. Therefore, if the cold stor- 
age portion were surrounded and divided by fire walls, openings 
properly protected and the electric wiring installed according to 
approved methods, it would seem that the fire risk was cut down 
to a minimum, as the nature of the machinery and the goods 
usually stored are not of an inflammable character. This point 
must, however, be appreciated by the fire underwriters to make 
it of any value to the storage man in the way of lower rates. 
That they will appreciate it in tlie near future there is no doubt, 
and then the requirements of fireproof insulation will seem un- 
necessary, except perhaps in the large warehouses in the large 

Coid storage warehouses have been erected on the lines indi- 
cated above with "mill construction" and wood insulation and 
have obtained a very low insurance rate, considering the general 
attitude of the fire underwriters toward the cold storage ware- 
house business. 

The necessity of fireproof insulation is felt in storage vaults 
for furs and fabrics, and justly so, as these articles are usually 
of great value and oftentimes could not be replaced if lost or 
damaged. This class of storage will permit a greater operating 
expense to offset the poorer insulating value of the fireproof in- 
sulation. Figs. 33 and 34 are details of the wall and ceiling 
insulation in the storage vaults of the Lincoln Safe Deposit Co., 
New York. The plaster blocks were fastened to the brick walls, 
every alternate block in every alternate row with iron anchors. 
The ceiling blocks were supported by tee irons, which in turn 
were suspended from the brick arches, as shown. These plaster 
blocks usually consist of plaster-of-paris and some binding ma- 
terial, such as manila fibre or common straw, and in the event 
of a severe fire they would probably fail and allow the filling 
material to fall out. The failure of plaster blocks was fully dem- 



onstrated by the recent Baltimore fire, where, in every case 
noted, partitions erected of them were completely destroyed. The 
company above named, in making later extensions to their plant, 
used cork blocks applied directly to the brick wall and plastered 
inside, as shown in Fig. 9. 


%L"^^ ■ —4 or MINERAL WOOL 

'^-''■'m\~~'^ PLASTER. BLOCK! 



?*j^*^-*trT' i ' J-V h:^ .iiAr* t*4 







Constructions such as shown in the two upper details of 
Fig. 22 are strictly fireproof and may be used where the tempera- 
ture difference between the inside and outside would not be more 
than 25° to 30° F. 



Figs. 35, 36 and 37 are reproduced from illustrations de- 
signed by Alfred Siebert.* These constructions were intended 



for brewery refrigeration where the temperatures required are 
comparatively high, as their heat transmission would be prohibi- 
tive for cold storage work. The difference of detail between Figs. 
35 and 36 is in the method of bonding the tiles to the main wall ; 







in the former case, som.e of the tiles are laid headers with one 
end secured in the brick wall and in the latter case iron anchors 
are used. 

fUMs^fifK p^i/f)//^f in pifi*h 



If a fireproof building is to be insulated where a slow burn- 
ing or fire retardant material can be used, a construction as shown 

• In "American Handy-Book of the Brewing, Malting and Auxiliary Trades." 



iNTtfintDlATr Tloor 


~ - -rcC^CfT rtETAi, LAtrt 


- ' iTFrhfLSAL. WDO. pLQCtC 

f — iWrnryrr tlooc- 



in Fig. 38 is the most practical and with the proper sheet or 
block material would be almost thoroughly fireproof. Such insu- 
lation can be finished inside with cement or plaster, as shown. 

The inside finish on the walls of the rooms is of some im- 
portance as a fire retardant. With the use of hard oils, var- 
nishes, shellacs, etc., the spread of a fire would be rapid, as 
these materials are very inflammable, but with the use of prepa- 
rations such as cold water paint or whitewash, the spread of fire 
would be retarded, as these mixtures are not inflammable, ano 
would give some protection to the woodwork on that account. 


The importance of thoroughly protecting the pipes that carry 
the cooling agent to the various parts of the storage building is 
as great as insulating the rooms. On account of the low tem- 
perature of these pipe surfaces, they condense much moisture, 


and if the covering is poor and not well protected on the outside 
from air leakage, a dripping and soggy condition is sure to follow 
each time the cooling agent is shut off. If this condition is once 
obtained the value of the covering is permanently impaired. 

There are some pipe coverings on the market, especially suit- 
able for bnne piping, made of cork or mineral wool in block form 
in the same manner as already described for wall insulation, 
and are made sectional to fit any size pipe or fitting, having the 
appearance shown in Fig. 39. Some of these sectional coverings 
are provided with canvas cemented to the sections with ample 
lap at the joints, and these laps are cemented together as the sec- 
tions arc put in place. Directions for putting on are usually sent 
with the material by the manufacturers. Hair felt is also a good 
material to use if properly applied, as indicated in Fig. 40, and 
can be handled very -.veil, if cut in lengths of five or six feet. 



wrapped around the pipe, and thoroughly wired with galvanized 
or copper wire. If a second layer is to be put on, waterproof 
paper should be put between the two layers and wired on, and the 
second layer then applied in same manner as above. The outside 
layer should have waterproof paper wired on and then covered 
with strip canvas, binding it on spirally with a good lap at the 
joints. The canvas must be bound on tight. The covering 
should then have at least two coats of a good elastic waterproof 

It is of primary importance that the pipes should be dry and 
should be given a coat of paint before covering is put on. The 







author recommends that the layers of covering should be thin, 
not more than one inch in thickness, and that at least two thick- 
nesses be used, having waterproof paper between each layer with 
cemented joints, so as to insure the air-tightness of the covering. 
For brine mains laid under ground, through brick walls or 
up through partitions, a covering of granulated cork mixed with 
hot pitch or asphalt is best, as described under cork materials. 
This method was used by the Quincy Market Cold Storage Co. 
of Boston, Mass., in running a street pipe line from one of their 
buildings to the other. The pipes were laid in creosoted plank 
boxes of proper size to permit sufficient space around them, and 
the mixture of cork and pitch was then poured iit. 



Fig. 41 illustrates a form of tunnel for underground brine 
pipes that has been used by the author. In this case, as shown, 
the tunnel was constructed of brick, waterproofed both inside 
and outside and the top constructed so as to be removable in case 
of necessity. The brine mains inside were covered in the usual 
way, leaving an unfilled space around them in the tunnel. 


The results of the penetration of moisture into the insula- 
tion has already been discussed under the various sub-heads ; and 
the functions of waterproof paper in the interior of the insulation 



to Stop this moisture, should by this time be pretty well under- 
stood. But the penetration of moisture through the masonry 
walls to the insulation must be prevented by special treatment. 

The tendency of masonry to absorb moisture is fully recog- 
nized and provided for in the building trades. It frequently hap- 
pens in heavy and driving rain storms, of some duration, that 
the water will be driven through a 9-inch and even through a 
13-inch brick wall. This is counteracted in general building 
operations, if it is desired to plaster on the inside of the wall, 
by constructing a 2-inch air space in the masonry wall. This 
space will prevent the passage of moisture sufficiently so as not 


to damage the plaster. A second method is to line the inside of 
a solid masonry wall with hollow brick or porous terra-cotta 
blocks. The third and most common method is to form an air 
space on the inside of the wall by vertical furring, and the lath 
and plaster is then put on. All of these methods have been used 
in cold storage warehouse construction, especially the last, as has 
been shown by the illustrations given. 

Basement walls are usually coated on the outside with 
cement and pitch or asphalt to prevent the moisture in the soil 
from penetrating to the inside. If the soil is very wet and there 
is danger of the water level reaching above basement floor at 
some periods of the year, as is often the case in some localities, 
there should be a dampproof course extended under basement 
floor, through the masonry walls and up on the outside of them 
to grade. This work belongs to building construction rather than 
to our present subject and it is therefore unnecessary to treat of 
it in detail. The position of this damp course is indicated in 
Fig. 30. 

The common method of protecting the insulation from the 
moisture in the masonry walls is to coat the walls on the inside 
with various preparations, such as paraffin, pitch, asphalt, etc. 
These are usually put on hot in a liquid state. No preparation 
having a strong penetrating odor, such as coal tar, should be 
used, as it is liable to taint the goods in storage. Pitch, if prop- 
erly put on, makes a fair coating, but on account of its quick 
hardening and brittleness, it is very difficult to apply in cold or 
even cool weather, and when cooling it will contract and fine 
cracks will appear running in every direction. To avoid this, 
the roofing men will mix coal tar with it to give elasticity, but 
it is then, of course, unfit for the inside walls of cold storage 
rooms on account of the odor, as stated. 

The best material for coating inside walls is pure asphalt, 
and it is specified almost exclusively by the author for this pur- 
pose. This material is odorless after it is applied, the odor given 
off when subject to heat is not penetrating and quickly disap- 
pears. Unlike coal tar or pitch, which are products of distilla- 
tion from gas works, pure asphalt is a natural mineral bitumen, 
and although it is similar in appearance to pitch, it is not so 
dense or brittle and it has sufficient elasticity so that it will not 


crack when cooling. Besides the commercial paving asphalts 
which are very impure, there are also refined asphalts on the 
market which are claimed to be over 90 per cent pure. These are 
the product of distillation from the oil wells of Texas and Cali- 
fornia, and because they contain a higher percentage of bitumen 
are more elastic than the paving asphalts. Asphalt is difficult to 
apply to cold storage walls on account of quick hardening, but 
not so much so as pitch. The chief difficulty, especially in small 
cities, is to obtain a pure asphalt and also to get workmen who 
have had experience in applying it. The local roofing men have 
little or no need of pure asphalt, as the common material for flat 
roofs in this country is pitch and coal tar, and consequently they 
do not carry asphalt in stock. In fact, many of them are under 
the impression that asphalt, pitch and coal tar are the same thing 
and will attempt to use the latter materials when asphalt is 

The commercial paving asphalt comes as a solid cake in 
barrels weighing from 500 to 550 pounds and containing, when 
melted to a liquid, about fifty gallons. The refined asphalts come 
also in 250-pound barrels, containing twenty-five gallons. As- 
phalt is melted in large kettles, such as used by roofers, without 
the addition of any oils or coal tar. Care should be taken not 
to boil the asphalt, as its natural oils are thereby evaporated, and 
when cooled down it will become more brittle. This mistake is 
very likely to be made by the ordinary roofer, because asphalt 
melts and boils at lower temperatures than pitch. The hot 
asphalt should be applied to the surfaces with string mops to get 
the best results, the process is slow and tedious on account of 
the heavy consistency and its quick cooling. The surface should 
afterward be examined and all holes and crevices pointed up 
with asphalt. If the walls are dry and the weather warm, a gal- 
lon of asphalt will cover about thirty square feet of ordinary brick 
surface ; in cold weather a gallon will cover about twenty square 
feet, or 6,000 and 4,000 square feet per ton, respectively. Where 
the walls are very rough or constructed of rubble masonry the 
asphalt coating will not cover much more than 3,000 square feet 
per ton. The surfaces that are to be coated must be free from 
frost or ice, and should be thoroughly dry to obtain the best re- 


While a good coating of asphalt on inside of wall will pre- 
vent moisture from reaching the insulation, it does not water- 
proof the brick wall itself. Brickwork full of moisture is a much 
poorer insulator than when dry, and as we should get the great- 
est insulating value possible out of the construction, it is evident 
that the outside of the walls should also be waterproofed. There 
are a great many preparations on the market that are being used 
for waterproofing external walls with more or less success, but 
as they will all oxidize and disintegrate in time, the coating has 
to be renewed at intervals to prevent the absorption of moisture. 
The coating may receive proper attention when applied for the 
first time, just after the building is erected, but it is very likely 
that necessary future coatings will be neglected or forgotten; on 
this account it is not safe to rely upon the outside coating only, 
the inside walls should also be waterproofed as indicated above. 

Boiled linseed oil is often used on external walls with very 
good results. If three coats are first given, one coat applied 
every three to five years thereafter will be sufficient. The oil 
does not change the color of ordinary brickwork to any extent, 
but tends to give it a darker and richer appearance. 

White or red lead, ground in boiled linseed oil, is more 
durable than the oil alone, but it entirely changes the appearance 
of the building and in most cases would not be permissible on 
that account. New work should not be painted until the walls 
have been finished two or three months, and at least three coats 
should be given the first time. The above two preparations are 
probably as good, if not better, than any of the patented prep- 
arations on the market. 

Cabot's Brick Preservative, made in Boston, Mass., has been 
used in general building operations as a waterproofing quite 
extensively, and, it is claimed, with good success. This prepara- 
tion is made both colorless and with a red color, so as to be adapt- 
able to any color of brick, and it is applied with a brush in the 
same way as oil, no heat being necessary. 

Mr. Stoddard, in his paper oh "Insulation," previously re- 
ferred to, describes in detail tests on the waterproofing of brick, 
using various preparations and materials. These tests are about 
as complete as anything that has been attempted in this line, and 
being pertinent to the subject, are given in full, as follows: 


During the summer of 1899 a large variety of paints, oils, varnishes, 
cements and so-called waterproof coatings were tested for a cold storage 
company in the hope of finding some coating that would make waterproof 
and airproof the brick walls of its warehouses. The tests were made with 
quarter bricks with good, fair surfaces, free from large holes, and, as 
nearly as possible, like those used in the exterior walls. Quarter bricks 
were used instead of \vhoIe bricks, so that sensitive balances could be 
used for the different weighings. All weighings were made to within one- 
thousandth of a gram. The results of the more satisfactory tests are 
tabulated below, and besides these, many other tests were made, but they 
were either unsatisfactory or the materials tested of no value for the 
desired use. The quarter bricks to be tested were immersed in water of a 
temperature of about 70°. the brick being placed on its side, with one inch 
of water over it. Weighings were made as follows: 

Of the brick before coating. 

Of the brick after coating. 

Of the brick after immersion 24 hours. 

Of the brick after immersion 48 hours. 

Of the brick after immersion 72 hours. 

Of the brick after immersion 96 hours. 

Of the brick after immersion 120 hours. 

At the end of each twenty-four-hour period the quarter bricks were 
taken from the water, the outer surfaces carefully dried by cloth and 
blotting paper, and then the bricks were immediately weighed before any 
evaporation could take place from the pores of the brick. This was 
repeated in most of the tests until the bricks had been immersed for a 
period of 120 hours. After this continued immersion the bricks were taken 
from the water and their surfaces examined in order to see what change, 
if any, had taken place in the coating. In some cases the coating had 
softened, in some shriveled, and in one case the coating, naphtha and a 
paraffine-like substance, which before immersion was evidently well into 
the pores of the brick, had gradually worked out into the water. 

The nature of the substances tested varied greatly. Some were in 
the nature of paints and varnishes, and were retained mostly upon the 
surfaces of the bricks. To this class belonged the materials used in 
tests marked A. B, D, G, L, O, P and Q. Other substances were more in 
the nature of a paste or coating applied upon the surface of the bricks. In 
this class may he included the substances used in tests marked C, I, K, 
N, R, S, T and U. Another class of substances was supposed to soak into 
the bricks, and by filling the pores exclude moisture. To this class be- 
longed the substances used in tests E, F and J. Other coatings consisted 
of two substances, which, when combined, were supposed to form an 
insoluble compound or compounds which would fill up the pores of the 
brick. The tests of this class are marked H, M and V. 

Some substances which were submitted for test could be applied to 
the bricks only by soaking, and so were not available. Some bricks 
offered for test were soaked full of the so-called waterproofing, and of 
course would not absorb water or anything else while in that condition, 
as the pores of the brick were already filled. Many resins, gums and oils 
were tested, but were of no practical use. 

Pitch, asphaltum, etc., were objectionable, because of their odor and 
color. The results of the tests giving the most favorable results are as 
shown in following tables: 

In regard to the result of the tests it is worthy of remark that some 
of the substances that have been considered as among the best waterproof 
materials proved to be either of little value or very inferior to some of the 
other substances. 





























c Si 


































































































































































































































:::::::: ::::::: ;:::::: 

:::::;• ::::::: ::::::: 

::::::: :::.::: 









* Compared to coated brick. 1 gram equab 15.43 grains; 28.35 grams equals 1 ounce avoirdupois. 

A. — Bay State air and waterproofing 3 coats. 

B. — Red mineral paint, ground in oil 2 coats. 

C. — Spar varnish with plaster of paris 2 coats. 

D. — Spar varnish 2 coats. 

E. — New York sample, No. 2 Soaked. 

F. — New York sample, No. i Soaked. 

G. — Shellac i coat. 

H. — Portland cement, i coat; soap and alum, 3 coats. 4 coats. 

I. — White enamel paint 3 coats. 

J. — Paraffine in naphtha 3 coats. 

K. — Hot paraffine 3 coats. 

L. — Water paint 3 coats. 

M. — Portland cement mixed with Ca Ci», i coat. 

Water glass, 3 coats 4 coats. 

N. — Portland cement 2 coats. 

O. — Black varnish. No. 2 3 coats. 

P. — Spar varnish i coat. 

Q. — Black varnish, No. i 3 coats. 

R. — ^Waterproofing. No. i. 

S. — Waterproofing, No. 4. Similar to "R." 

T.— Waterproofing, No. 3. Similar to "R." 

U. — Waterproofing, No. 2. Similar to "R." 

V. — Bi-chromate potash and glue — exposed to sunlight. 


The Sylvester process, H, soap and alum, proved to be of little 
value, even when applied to a surface made as smooth as possible with 
Portland cement. This process was also tried without the cement, but 
was even less effective. Hot paraffine has often been used to waterproof 
walls ; but, under the conditions of these tests, it proved to be very far 
from waterproof. Portland cement is another substance which did not 
prove to be as good as its reputation. 

Of all the materials tested, those used in tests A, B, C and D ren- 
dered brick, to which they were applied, more nearly waterproof. Spar 
varnish, used in tests C and D, was very good under test; but it is a 
very expensive material, and will withstand exposure to the weather 
only for a rather limited time. 

The material used in B was a common mineral paint ground in oil. 
It was very good under test; but the best authorities on paint predicted 
for it a very short life in actual use, as it would disintegrate after a 
short time by the oxidation of the oil. 

The substance used in test A not only proved to be the best water- 
proofing substance of any tested, but it seems to have all the qualities 
necessary for the coating of the outside of brick walls. It is moderate 
in price, and is easily and quickly applied, being put on with^ brush the 
same as a varnish or paint. When applied to a brick wall, it forms a 
glossy, hard, transparent coating, and, instead of defacing the wall, it 
greatly improves its appearance, making the common brick look like 
enamel or glazed brick. The substance is a specially prepared and highly 
oxidized oil that has been and is used in the best varnishes. As it is 
thoroughly oxidized in its preparation, exposure to air should affect it 
but little,, and it should not need to be renewed for many years. The 
brick wails of a number of large warehouses were coated with this sub- 
stance one and two years ago, and the coating is apparently as good as 
when first applied. One gallon will cover from eighty to loo square feet 
of surface with three coats, the first coat taking considerable oil, but 
each successive coat taking less. A brick wall should be as dry and 
warm as possible when the coating is applied. It should not be applied 
to a damp wall just laid, or when the outside temperature is below 40° F. 
This oxidized oil is known commercially as "Bay State Air and Water- 

If the coatings of this substance continue to wear as well in the 
future as they have in the past two years, the substance will prove of the 
greatest value for airproofing and waterproofing the brick walls of cold 
storage warehouses. Any efficient waterproofing that can be applied to 
the outside surface of a cold storage warehouse is of the greatest import- 
ance, as there is where the entrance of moisture would best be stopped; 
but this outside coating should not be depended upon alone to prevent 
the entrance of moisture into the warehouse, and there should always 
be inner layers of some air-tight material, like an air-tight paper, with 
the joints cemented. 

If we make use of a durable insulating material of good efficiency, 
apply it carefully and of a proper thickness, and make it air tight and 
moisture proof, we have done all that is practical to well insulate a cold 
storage warehouse. 

A better method than using preparations will, in the opinion 

of the author, be used in the future for waterproofing external 

walls. This is to face them with glazed brick or salt-glazed 

terra-cotta blocks, laid with thin joints or rich cement mortar. 

The glazing is absolutely waterproof and w-ould last for an in- 


definite time, but the present cost of glazed brick would make 
their use almost prohibitive, as they cost from $80.00 to $ioo.oo 
per thousand. Glazed terra-cotta on tile in the form of hollow 
building blocks can now be obtained, and are used as a facing 
for outside walls in the same manner as pressed brick. In this 
position these blocks, if properly laid, will practically prevent 
the absorption of moisture, and would cost about the same, laid 
in the wall, as selected common brick. 


There are very little reliable data available on the cost of con- 
structing msulation. This is owing mostly to the fact that this 
kind of construction is comparatively new in the building trades, 
and is usually done by the cold storage men with day labor. As 
a rule no separate accounts of costs are kept, as it is not apparent 
to the owners what future service such information would yield — 
they do not expect to build any more cold storage houses. There 
is also the variable factors of labor and material which may affect 
each locality differently, often to the extent of 50% difference 
in cost. This is of course true of all building operations, but 
especially so of constructing insulation, as the work is new and 
unfamiliar to workmen generally. All these conditions make it 
difficult to determine the cost of any particular insulation, with- 
out knowing exactly the conditions of each individual case. 

The advantages of sufficient and properly constructed insu- 
lation will usually appeal to the prospective cold storage man 
until the question of cost is brought up. It is the mistaken idea 
in general that when the building proper is finished, the greater 
part of the investment necessary for a complete cold storage 
house is expended. The construction of a cold storage house 
may be divided into three general operations; first, construction 
of the building proper; second, insulation; third, machinery or 
cooling apparatus. The additional cost of the insulation may 
generally be taken as one-half to two-thirds the cost of the build- 
ing proper. 

Generally speaking, the cost of insulation, erected in place, 
for temperatures of 30° F. down to 0° F., will be from about 25 
cents up to 50 cents per square foot, in proportion to the above 
temperatures. The Nonpareil Cork Manufacturing Co. gives the 
cost of the construction, shown as style No. 20 in Fig. 21, as 



about 22 cents per square foot ; that shown as style No. 13 in Fig. 
21 as about 38 cents per square foot, and that shown as style No. 
16 in Fig. 21, as about 48 cents per square foot. A construction 
shown in Fig. 24, with air space next to the brick wall, four 
^-inch boards and twelve inches of shavings, will cost from 20 
to 25 cents per square foot. A construction shown in Fig. 30, 
with eight inches of shavings and two inches of hair felt, sheet 
cork or mineral wool blocks, may be constructed for 25 to 28 
cents per square foot. This construction is suitable for tem- 
peratures of from 30° to 35° F. This construction shown in the 
lower part of Fig. 30, wliich is suitable for a temperature of 
20** to 25° F., may be constructed for 28 to 32 cents per square 
foot. A construction of the same character suitable for tem- 
peratures of from 5° to 10° F. may be built for about 40 cents per 
square foot. Referring to the five constructions shown in Fig. 
28, giving the same insulating value for various thicknesses of 
different materials, and comparing the hair felt with the air 
space and wood board construction, there is a total thickness of 
eight inches with the hair felt partition, and a total thickness of 
thirteen inches with the board and air spaces ; giving a difference 
of five inches in thickness with the same insulating value. The 
hair felt construction would cost from 35 to 40 cents per square 
foot, and the board and air space construction would cost 30 to 
35 cents. 

The waterproofing of the brick walls has been included in the 
estimates given above. The cost of waterproofing wfth hot as- 
phalt, when that product can be obtained at $40.00 per ton, will 
be about 2>4 cents per square foot. Waterproof and odorless 
papers cost from $2.50 to $5.00 per roll (1,000 square feet), 
depending on the thickness and quality. 

The insulating material in the form of blocks or sheets, such 
as mineral wool block, sheet cork and hair felt, varies in cost 
from four to six cents per square foot per one inch thick. This 
does not include freight, which would increase the cost, depend- 
ing on the locality. Mineral wool is sold by the pound or ton 
and can be obtained at from $25.00 to $30.00 per ton. 

The cost of planer mill shavings is variable, depending upon 
the proximity to the mills, season of the year, etc. In some 
cases known to the author they have been obtained for the mere 


trouble of hauling them away, but in most cases they are sold, 
either by the load or by the bale. The cost per bale of 80 or 100 
pounds varies from 15 to 25 cents. 


On account of the special character of cold storage insula- 
tion, the work should be carefully and frequently inspected to 
see that the materials are of the quality specified and that the 
work is executed according to details. The construction of in- 
sulation requires more care in the way of tight joints and first- 
class workmanship throughout, than is usually obtained in ordi- 
nary buildings. The labor required is mostly such as belongs to 
carpenters, and as they are accustomed to do work along certain 
lines common in ordinary building operations, it is sometimes 
difficult to train them into the high class work necessary for cold 
storage insulation. It must be constantly kept in mind that the 
insulation must be air and water proof. The materials and the 
combination in which they are used, no matter how excellent they 
may be, are much decreased in insulating value if these points 
are neglected. The materials, as they arrive at the work, should 
be inspected to determine if they are dry, and they should be 
kept under cover until used, to prevent them from becoming wet 
or damp. Planing mill shavings are sometimes damp when they 
arrive at the work and the bales should be loosened up and spread 
out in the building to allow them to air dry. The materials 
should be delivered sufficiently in advance to admit of proper in- 
spection and of being replaced with new material, if found un- 

The superintendent should see that all filling materials, such 
as granulated cork, mineral wool, shavings, etc., are properly 
packed into the spaces to about the proper ^ensity. (See Mate- 
rials.) The prevention of the future settling of the filler is 
mainly a question of personal care in seeing that it is properly 
packed, and all corners and tops of filled spaces, which are diffi- 
■cult to pack, will need particular attention. The waterproof 
papers, as already stated, are used to prevent the passage of air 
and moisture and their application, therefore, is of prime im- 
portance. All joints should be lapped two or more inches, and 
•each course of papers should be lapped around corners and angles 


of rooms. In case the paper should be torn by the workmen, it 
should be replaced or another sheet should be placed over it. All 
sheathing and matched boards should be free from large or loose 
knots, should be fitted up close in all corners and angles, and 
nailed at bearings only. No nails should be driven through 
boards and paper, and project into the filled spaces or into the 
sheet material. As a proper finish for the inside corners and 
angles of rooms and around door jambs, the author recommends 
and uses ^-mch or J^-inch quarter-round mouldings as giving 
air-tight, neat-appearing and serviceable finish. 




A circulation of air is necessary to produce the best possible 
conditions in a cold storage room, and this necessity is now real- 
ized by the most progressive people engaged in the business. 
Considerable controversy has taken place between those who 
advocate the cooling of rooms by piping placed directly in the 
room, and those who have adopted some form of fan or forced 
circulation in which the pipes are placed in a coil room or entirely 
outside the storage room, and the air distributed through the 
room by means of air ducts. The people who have been longest 
in the business do not like to believe that any improvement can 
be made on placing the pipes in the room, and insist that they can 
turn out as good stock as their more progressive competitors 
who use some form of forced circulation. To substantiate this 
argument, they refer to So-and-so who tried fans and had to put 
pipes in the rooms to hold his temperature, and claim that the 
results from the forced circulation system are no better than from 
the old methods of gravity air circulation. This argument is 
not sound, and it is proposed in this chapter to show clearly why 
a circulation of air is necessary, and also why a positive circula- 
tion, by means of fans, with a proper system of air distribution, 
is better than direct piped rooms, or any circulating system 
which depends on a difference of temperature in the air in differ- 
ent parts of the room for its operation. 

Notwithstanding the attention which this subject has at- 
tracted, and the resulting discussion, there is yet much which is 
but imperfectly understood, such as the confusing of the terms, 
"air circulation" and "ventilation." The two are as distinct as 
can be, and it should be borne in mind to begin with that ventila- 
tion is what the name implies — the introducing of fresh air from 


an outside source for the purpose of purifying the room. Circu- 
lation refers only to the movement of air within the room, and in 
no case should the term, "ventilation," be applied to this sub- 
ject in connection with refrigeration. Ventilation is mentioned 
only in explaining the difference between the two, and is not 
under consideration here, but is taken up in a separate chapter. 
Our present subject for discussion is air circulation in refriger- 
ated rooms — the same air over and over — and has no connection 
with the supplying of outside air. To the end that the misunder- 
stood features of the subject may be cleared up somewhat, the 
history and underlying principles of refrigeration and air cooling 
will be taken up, to show as clearly as possible the gradual devel- 
opment of the industry leading to the systems and methods of 
cooling now in use. The advantages of a forced circulation of 
air in cold storage rooms will be so plainly demonstrated that 
any thinking man must acknowledge them. 


The most primitive form of cold storage consists in employ- 
ing the comparatively low temperature to be obtained in cellars 
or caves for the keeping of products subject to rapid decompo- 
sition. In this way they are protected from the extreme heat of 
summer, and to this extent preserved by a natural source of re- 
frigeration. In this crude form of cold storage, air circulation 
was unknown, and if any existed it was by accident. Articles 
placed in a cellar or cave are cooled by radiation or conduction 
from the earth altogether, and not by a circulation of air. After 
caves and cellars, natural ice was employed for cooling purposes, 
and came quickly into general use, for the reason that lower 
temperatures and a dryer air were to be obtained. For cooling 
purposes, ice was first stored in underground pits dug in the 
earth, with the idea that the melting of the ice would be retarded. 
Goods for preservation were placed on or within the mass of ice. 
This was an improvement over the use of cellars in the matter 
of temperature only. Even after the ice house was placed above 
ground and provided with insulated walls, the favorite method 
was to build a room within the ice house, and surrounded on 
three sides by the ice, for the storage of goods to be preserved. 
Circulation of consequence did not exist, and goods placed there- 



in quickly deteriorated, caused by a growth of mold and a musty 
condition of the air, induced by a very moist atmosphere. 

A bit of personal experience will serve to illustrate some of 
the early phases of ice cold storage. About the year 1875 the 
author's father constructed a large ice house adjoining a cheese 
factory and creamery. In one corner of the ice house, and open- 
ing into the creamery, was built a fair sized room for the storage 
of butter. The ice was placed on top of this room and also 


against two of its sides. Openings were provided at the top for 
the cold air from the ice house to come into the room, but no 
circulation of consequence took place, because the laws governing 
air circulation were not given proper attention. A large part of 
the cooling in the room was by direct conduction through its 
walls. The room carried fairly cold, at about 37** F. A large 
block of fine creamery butter was stored in the room for about 
three months. When removed, the tubs were very moldy, and 
the butter as well ; the butter, even during the short time stored, 



being decidedly injured in flavor. This room was very damp, 
the ceiling and walls showing very wet, and moldy to some ex- 
tent. In the light of present experience, this method of storing 
butter seems absurd, and it is mentioned simply to illustrate how 
a lack of circulation and some means of absorbing the moisture 
will cause bad symptoms in a cold storage room in a compara- 
tively short time. Fig. i illustrates the construction of this room, 
in the corner of the ice house. It will be noted that no flues were 
provided to conduct the warm air to the top of the ice house, 
and the cold air toward the bottom of the storage room. Open- 
ings from the ice chamber only were provided, and this will not 
promote a circulation of air except under accidental conditions. 

Shortly after the above related experience, a large room in 
the basement of the stone store building was fitted up for the 





:f ^ 


^ORKQL r\p(M{ 



/ / 






storage of cheese. This was built on the side icing plan, the ice 
being placed in a rack or crib along one side of the room, which 
was about twenty-five feet wide. The room was insulated by 
studding and sheathing against the walls, and filling behind with 
sawdust. It was surprising to see the ice disappear, and the 
temperature could not be held below an average of 45° F. This 
room was superior in one respect, however, to the butter storage 
room just described. It had a fairly strong circulation of air 
as long as the ice rack was kept full, and cheese came out in fair 
condition, though moldy, after a three or four months' carry. A 
serious drawback to the successful working of the room was that 
when the ice was partly melted in the ice rack, the top of the room 
would become much warmer than near the floor. This was 
especially noticeable during warm weather. When the ice rack 


was full this condition was greatly improved, but when the ice 
was much reduced, the air at the top of the room became warm 
and dead. Fig. 2 illustrates a full ice rack and a comparatively 
perfect circulation of air to the top of the room. Fig. 3 shows a 
sluggish circulation, with a dead stratum of warm air at the top 
of the room, resulting from the small quantity, and location of 
ice in the rack. 

As a natural improvement on the side icing plan mentioned 
above a structure two stories high was constructed, with ice at 
the top and storage space below. The ordinary domestic refrig- 
erators are mostly built on about this plan, and this idea has 
been developed to the fullest possible extent. Many patents have 
been granted to inventors for improvements in details of con- 


wwf{ft fln^rrit orsit/^ 


-_ /l 

COLO ^rt^irnt armn 



struction and the promoting and control of circulation in cold 
storage rooms with overhead ice. Fig. 4 shows why overhead 
ice produces a good circulation, if properly designed, with up 
and down flues. Prominent among the old overhead ice systems 
are the Jackson, Stevens, McCray, Dexter, Nyce and Fisher. 
These systems, as compared with any method of end or side 
icing, are markedly superior, and many of these old houses are 
still in service. Any system using natural ice only as a cooling 
agent is now considered obsolete, when compared with the pres- 
ent day methods of air cooling by means of chilled pipe surfaces 
in the form of brine or ammonia piping, but in the early days of 
cold storage these old systems were very satisfactory. Circula- 
tion of air may be mentioned as the keynote of whatever success 
was attained by the overhead ice systems. So much for the value 



of a circulation of air in any room cooled by ice. It has been 
proved in practice that a circulation of air is necessary in such 


a room. It is equally true of a room cooled by metal surfaces 
through which a refrigerant at a low temperature circulates. 


A penetrating and fairly strong circulation of air is absolutely 
necessary in cold storage rooms because it is a part of the process 
which purifies the air. Nearly all goods which are ordinarily 
placed in cold storage for the purpose of retarding decomposition 
give oflf moisture. Along with the moisture given off are impuri- 
ties in the form of finely divided decomposed matter from the 


surface of the goods. Gases resulting from surface decomposi- 
tion, and the ripening of the goods in some cases, are also pres- 
ent. Besides the moisture given off by the goods, other moisture 
is continually finding its way into cold storage rooms by the 
opening of the doors, leakage through the insulation, and from 
the lungs of persons present in the rooms, all of which contains 
a greater or less percentage of impurities. These last sources 
are small in comparison with the amount of moisture and im- 
purities given off by the stored goods, but, nevertheless, are quite 
large in some cases, and worth considering. To prove beyond 
a question that goods give off large quantities of moisture and 
impurities, it may be well to consider what would be the result 
should the moisture and impurities be allowed to accumulate in 
the storage room. Let us assume an absolutely tight room, 
cooled from an outside source without exposed pipe surfaces or 
other means of taking up the moisture and impurities which are 
contained in the air of the room, say a room within another room, 
the outside room being cooled, and taking up all heat from the 
inside room. An experiment conducted by the author, described 
in chapter on *' Eggs in Cold Storage," under the heading of 
" Packages," illustrates fully the necessity of taking up moisture 
as given off by the stored goods. These experiments demonstrate 
conclusively what would result if goods were placed in a refrig- 
erated room which did not contain means for absorbing the moist- 
ure and impurities that are given off by the stored goods. It is 
imperative that the moisture be continually removed from a cold 
storage room containing moisture-giving goods. 

The relation between moisture and impurities in cold storage 
rooms is very close, as these elements are united to a large ex- 
tent. It is a well known fact that water has a great affinity for 
impurities of various kinds. The same is true of water in the 
form of vapor or moisture in the air of cold storage rooms, which 
has a great attraction for the gases and impurities which are 
given off by the stored goods. In fact, it is probable that the 
greater part of the impurities never part company with the mois- 
ture when they are both exhaled by the goods. It is, then, easy 
to understand that a room which has means of absorbing moist- 
ure also has means of purifying the air, and that the air is puri- 
fied to a large extent in proportion to the thoroughness with 


which it is circulated and brought in contact with the means for 
absorbing moisture. It must not, however, be understood that 
the air of a cold storage room is absolutely purified by having 
the moisture removed. There are gases which have little or no 
affinity for moisture which cannot be disposed of in this way. 
Fresh air must be supplied to maintain perfect conditions in cold 
storage rooms where goods are stored for long periods. (See 
chapter on "Ventilation.") If a cold storage was perfectly puri- 
fied by the removal of moisture there would be no odors of con- 
sequence present in such a room. How many cold storage rooms 
has the reader ever seen that were free from noticeable odors? 
Probably the worst form of impurity which is met with in 
cold storage rooms is the germs which produce a growth of 
fungus, or mold. These germs are no doubt present in the at- 
mospheric air everywhere. Their presence is manifested only 
under certain favorable conditions of moisture and temperature. 
Conditions of excessive moisture in the presence of decaying ani- 
mal or vegetable matter, together with a moderate degree of heat, 
are favorable for a very rapid growth of fungus. It is a well 
known fact that in the dry mountain districts of California or 
Colorado freshly killed meat may be hung in the open air without 
decomposition. The air contains so little moisture that the germs 
W'ill not propagate. Fresh meat exposed in the same way in 
the moist, tropical climate of Florida or Cuba would be quickly 
decomposed so as to be unfit for food. Germs of mold and de- 
cay flourish in a warm, moist atmosphere, but quickly succumb 
where it is dry and cool. As the moisture is absorbed and re- 
moved from the air of a cold storage room, with it are largely 
removed the germs and other impurities. Low temperature 
pipe surfaces freeze the moisture from the air, and in this way 
a large portion of the impurities is disposed of. It may already 
have occurred to the reader to ask what all this has to do with 
air circulation in cold storage rooms. We have discovered that 
a room may be cooled from an outside source and still be an un- 
fit place for goods when no means of taking up the moisture 
are present. Even should the pipes be placed directly in the 
room, the results would be bad unless there is a circulation of 
air. A circulation of air is absolutely essential to a perfect cold 
storage room, because the air must be continually moving in con- 



tact with the pipe surfaces or other means of absorbing moisture. 
The question of what means are the best for removing the moist- 
ure from a storage room is not under discussion. Our problem 
is to ascertain the best means for circulating the air in contact 
with the means for absorbing the moisture. 


When mechanical refrigeration first came into the field, the 
arrangement of cooling surfaces and a provision for air circu- 
lation was neglected about as it was by the pioneers in natural 
ice refrigeration. The cooling pipes were placed almost any- 
where, regardless of the laws of gravity which control air circu- 
lation. At first the ceiling of the room was a favorite place for 



^ r 









locating the coils of pipe for cooling the room. The ceiling was 
utilized because thus the pipes were out of the way in piling up 
goods, and also on the theory that "cold would naturally drop." 
Cold, or, more accurately speaking, cold air, will naturally drop, 
but placing the pipes on the ceiling of a room will not assist the 
circulation; it will, in fact, produce practically no circulation at 
all if the whole ceiling of the room is covered with pipes uni- 
formly. Ceiling pipes have generally been abandoned for the 
more rational method of placing the pipes on the side walls of 
the room. Fig. 5 shows ceiling piping, and should make plain 
why no circulation is created when the pipes cover nearly the 


whole top of the room. The left half of the diagram shows the 
pipes covering the entire ceiling, the right half in two sections. 
Note the arrows showing the resulting circulation in each case. 
As is well known, cold air is heavier than warm air and, if free 
to move, the cold air will seek a lower level than the warm air. 
This movement of the cold air downward and the warm air up- 
ward is what is known as gravity air circulation. A slight dif- 
ference in the temperature will cause a circulation of air if the 
warm and cold air are separated from each other and not al- 
lowed to mix, which would cause counter-currents and retard 
the circulation. In a cold storage room, the air in contact with 
the cooling coils, as it is cooled, flows downward toward the 
floor by reason of its greater specific gravity. The compara- 
tively warm air above is drawn down to the pipes, where it is 
in turn cooled, and the flow is continuous. If the entire ceiling 
is covered with pipes, what results? The air in contact with the 
pipes cannot fall because it cannot be replaced by warm air from 
above. The result is that practically no circulation of air takes 
place in such a room. A slight local circulation in the vicinity 
of the pipes is all that results, except under unusual or accidental 
conditions. The goods are cooled for the most part by direct 
conduction and radiation; the top tier of goods would be cooled 
directly from the pipes and each tier under successively from its 
neighbor above in the same manner. Goods are cooled by radia- 
tion by the passage of heat from the goods directly to some colder 
object without the heat being conveyed by the movement of the 
air, as it should be, and as it is where a good circulation is pres- 
ent in the room. In a room in which the goods are cooled by 
radiation mostly, the moisture instead of being deposited entirely 
on the cooling pipes, as it should be, is also likely to be deposited 
on the walls or ceiling of the room, or on the goods themselves. 
The result of such a condition may be serious. This cooling by 
radiation, as compared with cooling by a circulation of air, may 
seem like a very finely spun theory to some, but let the skeptic 
watch his house for a demonstration. Is there any practical cold 
storage man now in the business who has not noticed an accu- 
mulation of frost or moisture on goods if they were piled too 
near to the exposed cooling pipes? What causes this result? 
Radiation — nothing else. 



The bad effects of radiation cannot be altogether overcome 
by placing the pipes on the sides of the room, but it is counter- 
acted to some extent by the resulting circulation of air. Fig. 6 
shows side wall piping and the resulting circulation, which is 


iSTf^FTn oruftf^M nir^ 

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confined largely to a small space near the coils. The arrows 
show approximately the path of circulation. If the room is wide, 
no circulation at all will take place near the center. In some 
cases pipes have been carelessly placed two or three feet down 
from the ceiling, as shown in the illustration. This results in the 
air of the room becoming stratified — a warm layer of air in the 


top of the room resting on a cold layer beneath. Figs. 2 and 3 
illustrate this clearly. This may be operative to such an extent 
as to cause a difference in temperature between floor and ceiling 
as great as 10** F. A case has come to the author's notice with 
exactly these conditions. Another bad arrangement of side wall 
piping was that of a room more than fifty feet square piped com- 



pletely around on the side walls from floor to ceiling, with the 
exception of the doors. No circulation could penetrate to the 
center of such a room, and conditions were very poor, in conse- 

The placing of a screen in front of the side wall piping, 
hung well up toward the ceiling of the room, as illustrated in 
Fig. 7, marks the first scientific step toward a betterment of air 
circulation in a room with direct piping. It prevents the action 
of radiation, and assists the volume, velocity and area of circu- 
lation, but does not well take care of the center of the room, 
although the increased velocity forces the air to cover a greater 
area and flow to a greater distance from the coils. The screen 
or apron should be of wood or any moderately good non-con- 




ductor. By separating the warm from the cold currents of air, 
the velocity is increased on the same principle that a fire burning 
in a flue creates a greater draft than when burning in the open 
air. Radiation is prevented in the same way that a fire screen 
protects one from a too hot fire in a g^ate, only the radiation, as 
already explained, is in a reverse direction. 

In Fig. 8 the same arrangement of apron is shown as in 
Fig. 7, but added thereto is the false ceiling extending out to- 
ward the center of the room. This addition to the perpendicular 
apron causes the air, after circulating over the coils, to spread 
out more toward the center of the room and cover the cross- 
sectional area much more uniformly. While it decreases the ve- 
locity proportionately, it is considered a superior arrangement to 
the perpendicular apron alone, placed in front of the coil. The 


false ceiling should have a slant of about one foot in twenty, and 
the opening on the outer edge near center of room need not be 
over four or five inches in depth in most cases. Without the 
false ceiling some space must be left for a circulation of air at 
the top of the room ; with it, the goods may be piled close up to 
the false ceiling, so no space of consequence is wasted in using it. 
The arrangement shown in Fig. 9 was first originated by 
Mr. C. M. Gay, and was described in the August, 1897, issue of 
Ice and Refrigeration. Barring the space occupied, it is by far 
the best arrangement of room piping now in use. The following 
is quoted from Mr. Gay's description : "Upper pipes of box 
coils should be about ten inches below ceiling of the room, to 
prevent sweating. [Sweating in such a case is caused by radia- 


FIG. 9. — MR. gay's arrangement OF ROOM PIPING. 

tion, as already explained.] When brine or ammonia is turned 
into these pipes the cold air around the pipes seeks an outlet 
downward, and passes between the false partition and the side 
wall of the room, thus displacing or pushing along the air in 
center of room, the cold air naturally seeking the lowest point 
and the warm air the highest point, each by reason of its relative 
gravity. Thus, as the cold air falls from the cooling surfaces 
it is replaced by the warm air from highest point in center of 
room. This secures a natural circulation and a dry room, there 
being no counter-currents nor tendency to precipitate moisture 
on walls or ceiling." Mr. Gay's remarks regarding his system 
apply with still greater force to the St. Clair system, and to a 
greater or lesser extent to any system which provides for a re- 
moval of the cooling pipes from the room. 




The St. Clair system, illustrated in Fig. lo, is sometimes 
called the pipe loft system, because the cooling coils are placed 
above the storage room in a pipe loft or coil room. This is a 
favorite arrangement where an overhead ice cold storage house 
is remodeled and equipped with the mechanical system. In this 
case the pipes are placed in a portion of the old ice room, and 
perhaps the old air ducts used for air circulation. If the storage 
house consists of several floors of storage the pipe loft may be 
placed at the top and the rooms below all cooled from one pipe 
loft, but a much better method is to have an independent coil 
room for each room, and circulate the air through separate air 





^////////////////////m: „ : //:- . , 




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ducts. This prevents contamination from foreign odors when 
different products are stored in different rooms. The circulation 
is more vigorous and effective with the St. Clair system than 
with any pipe-in-the-room system, depending on the law that 
the higher the column of air the stronger the draft, in the same 
manner that a tall chimney gives a stronger draft than a short 
one. The effect of this is to produce a good circulation of air 
with a comparatively small variation of temperature. The St. 
Clair system is also better because by suitable trap doors on the 
air ducts, the pipes may be shut off from the room, when the tem- 
perature is such outside as not to require the circulating of the 


refrigerant. The necessity of keeping the air of a storage room 
from contact with the frosted pipes when the refrigerant is shut 
off will be considered in connection with the forced or fan circu- 
lation system, to be described further on. 


We have seen how rooms for the storage of perishable prod- 
ucts are cooled by natural or gravity circulation or by direct 
radiation. Reasons have been given why each succeeding method 
was superior to the former one. It is very easy to see that 
where a room is cooled by direct piping, or by any system of 
gravity air circulation, the goods within such a room cannot all 
be exposed to the same conditions. Goods piled at the floor and 
near coils where the air circulates direct from coils are certainly 
exposed to a much colder air and stronger circulation than those 
farthest from coils and near the ceiling of room. Gravity air 
circulation, as its name indicates, depends on a difference in 
weight, and therefore a difference in temperature of the air in 
different parts of the room, for its existence, and there must, 
therefore, be varying temperatures in different parts of the 
rooms. The difference in temperature will range generally from 
2° to 5° F., with the best arrangements here described. The 
greater the difference the stronger the circulation, usually. With 
a difference in the temperature of the air in different parts of the 
room goes a variation of other conditions; especially as to dry- 
ness and purity of the air. 

Many cold storage warehouses, equipped in many different 
ways, even some of them cooled by natural ice, are producing 
results satisfactory to their owners; to use a familiar phrase, 
"are having good results." This is not at all surprising, when it 
is considered that a result which is satisfactory to one man would 
not be satisfactory to another; but it is very confusing to an 
interested person who undertakes to investigate the various cold 
storage houses of his acquaintance, with a view to ascertaining 
which system is best suited .to his needs. The variety of opinion 
expressed depends largely on the individual prejudice of the 
person giving the opinion. The investigator, if not fairly well 
posted on the subject himself, usually is so confused that he 
takes the advice of his most intimate acquaintance, and adopts 


some old time system which has been found reliable. This 
means, in a majority of cases, that he is adopting some out-of- 
date ideas for a new house, which should embody all the latest 
improvements. Should the investigator be a fair minded man 
and well informed on the subject, new improvements, with logic 
and practical results behind them, are adopted, after due consid- 
eration. Results are, of course, the final test, but it is very nec- 
essary that a person should have actual and not fancied results, 
and unless new ideas for improvement are investigated and 
adopted, cold storage men will get "behind the procession," the 
same as in other mechanical and scientific lines. \Vhen a new 
system or device can show results equal to or better than the 
older ones, costs no more to install and operate, and, further, is 
based on scientific principles and common sense, that system is 
the one to adopt. It will surely demonstrate its superiority in the 
long run. There are many in the business who still think that 
direct expansion piping placed directly in the room is the acme 
of perfection and cannot be improved upon. Argument for im- 
proved systems in such a case is useless. 

A comparison of the methods of heating our best public 
buildings in former years, with those in use at the present time, 
will show us the past and present, or rather the past and future 
of cooling the best cold storage houses. In years gone by, the 
best and most costly structures were heated directly by stoves, 
later by hot-air furnaces, and lastly by the indirect or fan sys- 
tem. A stove for heating a room may be compared with direct 
piping for the cooling of a storage room. We all know the dis- 
advantages of a stove for house heating — too much direct radia- 
tion, and a poor distribution of heat. The same may be said of 
a room cooled by direct piping, only it is the refrigeration that 
is poorly distributed. Cooling a room by the pipe loft system is 
about the same as heating a room with a furnace, with the disad- 
vantages common to both. The advantages of handling the air 
of a cold storage room by means of a fan are likewise com- 
parable with the advantages to be had from a well designed 
forced system of heating. The best heating work is now done by 
means of fans, and the best cold storage work of the future will 
be done by means of fans. To prove the advantages of the fan 
system of heating, it is not necessary that people should suffocate 


and die in a building heated by stoves or furnaces; neither is 
the fact that goods do not completely spoil or decay rapidly in a 
room cooled by direct piping any evidence that the fan or forced 
circulation system is not superior by far to the pipe-in-the-room 
or any gravity method. Unquestionably the fan system of heat- 
ing gives a control of temperature, humidity and purity of air, 
not obtained in any other way. The forced circulation system of 
cooling also gives a control of temperature, humidity and purity 
of air in a cold storage room, not to be had otherwise. 


The chief, and in fact the only objection known to have been 
urged against forced circulation for cold storage rooms is a 
fancied notion that it will lead to a greater drying out or shrink- 
age in weight of goods which are placed in storage for preserva- 
tion than if a system of gravity air circulation or pipes in the 
rooms were used. The author has searched long and faithfully 
for the origin of this old tradition, but has never been able to 
discover that it was founded on fact. At least none of the most 
modem houses employing the fan system, so far as known, have 
ever had complaints from excessive evaporation. The worst 
shrunken goods which ever came to the writer's notice were some 
eggs from a house cooled by direct expansion piping placed 
directly in the room. It is probable that the claim that goods 
evaporate or lose weight more in a room cooled by the fan sys- 
tem is wholly a matter of theory, based, no doubt, on the assump- 
tion that the air is circulated at a much higher velocity. It is 
well known that a movement of the air aids evaporation. Every 
intelligent housewife knows that linen hung in the open air to 
dry will be freed of moisture quicker when a moderately strong 
breeze is blowing than when the air is still. The same principle 
applies to the goods stored in a refrigerated room, but evapora- 
tion from the goods in storage is dependent not only on the 
movement of air in the room, but on the humidity or dryness as 
well. If the humidity is properly regulated no harm will result 
from a very thorough circulation of air, even at a brisk speed. 
It may have happened in the early days of fan circulation, that 
the air was rapidly circulated with little or no distribution, and 
the goods exposed directly to the blast of air where it was blown 


into the room were excessively evaporated ; but in the numerous 
houses designed by the author, and using one or the other of the 
two systems of air circulation described further on, no such 
trouble has been experienced. If the humidity of the air is at 
the correct point, and the circulation of air well distributed 
throughout the room, and not too strong, no excessive or dam- 
aging evaporation will occur, and where trouble from this cause 
has been experienced it will be found in every case that no sys- 
tematic control of humidity has been attempted. It is as easy to 
control humidity as it is to control temperature, if proper means 
are provided, and we go about it in the right way. Absorbents 
and ventilation are both useful for this purpose, but this feature 
of cold storage is not under consideration here, and is treated 
on elsewhere under the proper heading. 

\\'ith a positive and well distributed circulation of air, a 
storage room may be maintained at a humidity which would be 
dangerous if only a sluggish gravity circulation of air were in 
operation. A brisk movement of air in all parts of the room 
quickly removes the moisture and impurities from the vicinity 
of the goods, and carries them to the cooling coils, where they 
are, for the most part, condensed or frozen on the pipe surfaces. 
This should explain how goods may be carried in good condition 
and with very little shrinkage in a room where a well designed 
system of forced circulation is employed. Two of the houses 
designed by the author are used exclusively for the storage of 
cheese. It is well known that cheese loses weight very rapidly 
in cold storage, and the problem heretofore has been to carry 
the cheese reasonably free from mold, and with as little evap- 
oration as possible. Cheese has been stored in the houses re- 
ferred to for three months, with very little mold, and with no 
shrinkage from marked weights, and the proprietors assert that 
there is less shrinkage, even on "long-carry" goods, than diere 
was with the overhead ice system which they formerly had in 
service. This is a sufficient proof of the value of forced circula- 
tion for the cold storage of cheese. The same applies equally to 
other classes of goods. With a room equi])ped with anv of the 
gravity systems of air circulation, already described, the circu- 
lation of air cannot be regulated, because it depends on the tem- 
perature of the refrigerant (generally brine or aninionia > circu- 


lating through the pipe coils. As the temperature of the refrig- 
erant is regulated to suit outside weather conditions (lower in 
warm weather, and higher in cold weather), the velocity of air cir- 
culation is not constant, being least in the cold weather of fall and 
winter, when most needed. With a good system of forced circu- 
lation installed, the chief problem of the cold storage man is to 
employ a proper degree of humidity. (See chapter on "Hu- 
midity.") Our discussion now brings us to a consideration of 
the various methods of mechanical air circulation in use. The 
weak as well as the strong points of the various systems which 
have been put in operation will be considered, regardless of where 
or by whom originated. 


The simplest, and probably the most unscientific, form of 
mechanical air circulation in cold storage rooms is the small elec- 
tric fan. These fans are usually of the four or six-bladed disk 
type, of from twelve to eighteen inches in diameter, attached 
directly to the shaft of a J^ or J^-horse power electric motor. 
The electric current for operating is usually obtained from the 
socket for an incandescent electric lamp. Electric fans are usu- 
ally placed on the floor in the end of an alleyway, or in an open- 
ing in the piled goods, and are used for creating a flow of air 
from one extremity of the room toward the other. If the circu- 
lation IS strong enough, these fans tend to create a uniform tem- 
perature in the room; but, as the air from the fan will follow a 
path of least resistance, the circulation resulting from their use 
is largely confined to the alleyways and openings in the piles of 
stored goods — it does not penetrate through and behind the 
goods where it would be most useful. The use of this type of 
fan in cold storage rooms is of doubtful utility, and is liable at 
times to lead to a positive harm by causing a condensation ol 
moisture on the goods in storage, as a result of the warm upper 
stratum of air coming in contact with the cold goods near the 
floor of the room. In some cases electric fans have been used to 
propel the air from the cooling pipes, for which purpose they 
are placed in an opening in a screen or mantle covering the pipes, 
forcing the cooled air outwardly into the room. This is a first 
step toward scientific forced circulation, and is useful as far as 
it goes. In many cases the electric fan is useful only as a "talk- 


ing point," as it is likely to impress a person, who is not familiar 
with cold storage work, with the cooling power of the refrig- 
erating apparatus, to stand for a few seconds in the breeze cre- 
ated by one of these high-speed fans. Their use has been adopted 
to an extent not at all warranted by the results to be obtained, 
and they will no doubt be gradually discontinued as the fallacy 
of the idea becomes apparent. Those who use electric fans as 
above described, by so doing admit the superiority of forced cir- 
culation over the gravity system, and also admit that their rooms 
are in bad condition, and that some mechanical means of agitat- 
ing or circulating the air is necessary. Instead of such a poor 
makeshift it seems that they will eventually come to the idea of 
installing a scientific system of forced circulation. 

Having proved a circulation necessary, it is evident that a 
method which will cause the circulation to be continuous, and 
at the same velocity, regardless of outside weather conditions, 
etc., must be better than depending on natural circulation, which 
varies greatly with the varying conditions and appliances which 
produce circulation as we have already seen. It follows further, 
then, that the system which will produce a circulation which is 
continuous, and at the same velocity, and besides is uniformly 
distributed to all parts of the room, must be the most nearly 
perfect way of handling the air for cold storage rooms. Any of 
the methods of gravity air circulation in which the pipes are 
placed in the room or otherwise, as shown in Figs. 5 to 10, are 
dependent on the outside weather conditions, temperature of 
room, temperature of refrigerant in pipes, length of time goods 
have been in storage, etc., for their operation. A continuous and 
uniform air circulation can only be obtained by the adoption of 
some mechanical means, and is usually secured by the use of a 
fan of some kind. 


So far as known to the writer, the systems of forced circula- 
tion here described include all of the recognized equipments 
which have been installed in one or more prominent houses. The 
patent records show a large number of crude developments which 
have in most instances been abandoned without having been put 
into practical use. A system which has been installed in several 


large houses in the United States, and to some extent abroad, 
is what may be termed a primitive form of forced circulation. 
This term fully expresses just what the system is, as no method 
could be applied in a more crude way. It consists simply in 
placing the refrigerating pipes outside the storage room, and 
using a fan to propel the air to and from the room. Fig. ii 
shows a floor plan of a room so equipped. The air is forced into 
the room at each end, and the return air to coil room drawn out 
in the center as shown. Cold air in this connection is spoken of as 
being the air from coil room to storage room, and warm air is 
mentioned as the air from storage room to coil room. These 
terms are used relatively only, and will be employed in the de- 
scriptions contained in this article. It should be understood that 


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in actual practice the difference in temperature between the in- 
coming and outgoing air is very small. In a well designed sys- 
tem this need not be over two or three degrees at the most. The 
cold air inlets at ends of room are in some cases placed near the 
floor and in others near the ceiling, but further than this no distri- 
bution of air is attempted other than that resulting from the loca- 
tion of the inlet and outlet. Sometimes the ducts are arranged 
to force the air into the room at the center, and the return air to 
the coil room is taken out at the ends, or the cold air is allowed 
to flow from the several openings in a duct running across the 
center of the room, but no adequate distribution results from this 



Employing the forced circulation system in this way is very 
much like the indirect systems of steam heating as at first in- 
stalled. It is noticeable now that the best steam heating work 
provides a thorough distribution of the heated air throughout 
the apartments through a great many small openings rather than 
forcing a large volume of air into the room at one or two places. 
It needs no argument or demonstration to show that a room heated 
or cooled by air forced in at one or two openings must have 
varying degrees of temperature, humidity and circulation de- 
pending on the remoteness or proximity to the direct flow 


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1 1 

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of air from inlet to outlet, for the reason that the air from inlet 
always seeks the most direct path to the outlet and moves through 
the area of least resistance, usually through the center 
alley of room. This is a positive fact and not a theory. 
The author once visited a large room of the kind above de- 
scribed, and despite the manager's statement that he had tested 
in every known way and found conditions absolutely uniform, 
the author for himself saw a temperature variation of two de- 
grees, and this between two thermometers hung in the center 
alley of room at the same height from floor, and without any 
extraordinary conditions to cause such a variation. As a matter 
of fact the real diflferencc in temperature in this room between 
the coldest and warmest point could not have been less than 
five or six degrees. 



The longitudinal section of a room shown in Fig. 12 illus- 
trates a system of forced air circulation which has been installed 
to a moderate extent, but has not become as well established as 
the one first described. A false ceiling is provided for distributing 
the cold air from cooling coils at the top of the room, but as with 
the system just described, no collecting ducts are provided for 
the purpose of uniformly removing the air from the room. The 
air from coil room comes into the room through narrow, slit-like 
openings in the false ceiling, and is returned to the cooling coils 
through and by the disk fan located in the partition between coil 
room and storage room. It would seem that this is working 


inn AIR oucT 


counter to the natural laws of gravitation, although it may be 
looked at in another light also. It is often remarked that "cold 
will naturally drop," but this should not confuse us when study- 
ing the means for promoting circulation. If the cold air is ad- 
mitted to the room at the top, it w^ill of course fall to the 
floor if allowed to do so; but why admit the cold air at the 
top of the room if it is wanted at the floor? In a room 
fitted with direct piping the cold air does not drap through 
the goods in storage, but down over the cooling coils, and rises 
through the goods in storage as it is warmed. It would seem, 
then, that any method of distributing the cold air at the top of 
the room is wrong in principle, especially as no means of uni- 
formly drawing off the air at the bottom of the room is provided. 



When warm goods are placed in a room equipped in this way, 
the moisture given off as the goods are cooled must be very liable 
to collect on the cold false ceiling. To provide uniform tem- 
peratures and humidity with this system it is necessary to pro- 
vide a strong blast of air, which is to be avoided, as goods 
directly in front of the fan may be exposed to too great a drying 

The arrangement of collecting and distributing air ducts 
shown in the cross section of room, Fig. 13, has been installed 
in a number of houses in America, and, like some of the others, 
depends on the "cold will naturally drop" theory for its operation. 


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The arrows show the natural tendency of the air circulation 
from the cold air ducts on the sides of the room to the warm air 
collecting duct in the center. In some cases the cold air is dis- 
tributed in the center and collected at the sides of the room, and 
where the room is narrow only two ducts are used, as in Fig. 14, 
a cold air distributing duct on one side of the room and a warm 
air collecting duct on the opposite side. In every case the ducts 
are placed at the ceiling, on the theory that the air from cold 
air duct will drop and distribute itself along the floor before 
being drawn back to the coil room through the return duct. The 
openings provided in the air ducts of this system are usually 
square openings, fitted with sliding gates to regulate the flow of 
air into the room and its return to cooler. These gates are placed 



five or six feet apart, consequently a good distribution of air is 
not provided, and goods exposed to the rapid flow of air directly 
in front of the openings will get a much greater volume of circu- 
lation than is to be found in any other part of the room. When 
a room of this kind is filled with goods, preventing the air from 
falling from the cold air duct to the floor, no circulation 
of consequence will be obtained near the floor, for the reason 
that air will travel through path of least resistance, almost di- 
rectly from feeder duct to return duct, about as shown by the 

A method somewhat similar to the one just described is that 
in which the cold air distributing ducts are placed at the floor and 



the warm air return duct is placed at the ceiling, as represented 
by the cross sections of rooms, Figs. 15 and 16. In narrow 
rooms only one distributing duct is used, as shown in Fig. t6. 
In wider rooms two distributing ducts on opposite sides of the 
room at the floor are used, and one collecting duct at ceiling in 
center of room. This arrangement has the merit of operating 
according to the laws of gravity, but still lacks the thorough dis- 
tribution of cold air and collection of warm air, as shown in the 
system described further on. It is, however, considerable of an 
improvement on any of the preceding methods, and the author 
has demonstrated in actual service that it will produce fairly 



uniform circulation and temperatures with a comparatively gentle 
flow of air. This system is to be recommended for goods which 



do not give oflF much moisture. It is preferable to use numerous 
small holes rather than a few large openings in the supply and 
return ducts. 


The system shown in the cross section of room (Fig. 17) 
was developed by the author after some experiment and has since 
been improved by two successive steps, the details of which will 
be described. It was the old trouble of sluggish circulation, 
especially during the fall and winter, which impelled the author 
to experiment for its betterment. As an improvement over the 
small electric fan already mentioned, an exhaust fan was fitted 
up to take air from the cooling apparatus and deliver it to the 
rear end of the room through a perforated duct. The air was 
allowed to find its way back to the coils as best it could. 

This method was applied to a long narrow room, and cer- 
tainly was a decided improvement over the sluggish natural 
circulation which it superseded. Following this, the perforated 
false ceiling was applied, with distributing cold air ducts on the 
walls, as shown in Fig. 17. The cold air from coil room was 
forced into the side ducts and flowed into the room through a 
great number of small holes in the top, bottom and sides of the 


cold air ducts. The warm air from the room flowed upward 
through the small perforations in the false ceiling and through 
the space between the ceiling of the room and false ceiling and 
thence to the coil room, where the air was cooled, and caused to 
repeat the same circuit continuously. The first apparatus was 
clumsy and the proportions of the various parts not correct, but 
the efficacy of a forced circulation of air, and a thorough dis- 
tribution and collection of the incoming and outgoing air of a 
cold storage room so plainly proven, that a further development 
of the idea was undertaken. 

It was demonstrated by above described experiments that 
a comparatively small amount of air, well distributed and uni- 


FIG. 17. — cooper's first SYSTEM OF AIR CIRCULATION. 

formly drawn off at the top of the room after flowing upward 
through the goods in storage, would produce very uniform con- 
ditions throughout the entire area of the room. Following up 
this information, the apparatus was reduced to a more practical 
form by substituting one broad duct near the floor, as in Fig. 18, 
for distributing the cold air, in place of the two distributing ducts 
as used in the apparatus shown in Fig. 17. The top duct of the 
two did not accomplish any result of consequence, and was con- 
sidered objectionable, as the air passing from this duct to the 
false ceiling did not percolate through the goods to any con- 
siderable extent, and resulted, practically, in a loss of the work 
done by the air flowing from the top duct. Two ducts also made 
the apparatus more complicated. Using the broad single dis- 



tributing duct near the floor in combination with the false ceiling 
resulted in a very penetrating and uniform circulation of air, and in 
practical service it has been found to produce superior results. No 
practical objections have been urged against it. As shown by 
the arrows, the air is caused to cover very uniformly the entire 
cross-sectional area of the room. This was accomplished by 
perforating the distributing ducts with small holes, and so pro- 
portioning them that a larger part of the flow of air is from the 
bottom of the ducts. The ducts are also perforated to some extent 
on sides and top. By piling the goods a few inches off the floor 
the air from bottom of ducts flows under the goods and out to 

FIG. i8. — cooper's improved system of air circulation. 

center of room. This action is also assisted by having the greater 
number of the perforations in false ceiling in the middle third or 
quarter of the room, so as to draw the air out from sides of room. 
As indicated by the arrows, the air moves up from the distribut- 
ing duct, is drawn into space above false ceiling, and returned 
to coil room to be cooled. 

The system described in the foregoing paragraph is nearly 
theoretically perfect so far as a uniform circulation of air is 
concerned, and a more thorough method than any of its prede- 
cessors, but it still remained to design the perforated false floor 
and false ceiling combination (Fig. 19) to produce a system which 


cannot be improved upon theoretically. Not only is the system 
theoretically perfect, but its practical application is so simple as 
to be unobjectionable. As shown clearly by the sketch, the flow 
of air is directly upward from floor to ceiling, consequently all 
goods piled in such a room are exposed to exactly the same con- 
ditions as to circulation, temperature, humidity and purity of 
the air. In a room equipped with this system, with the parts 
correctly proportioned, it is entirely safe to pile goods closely, 
only allowing a fraction of an inch between the packages and 
at sides of room and placing thin strips beneath the goods to 
allow air to flow from perforations in false floor. Where, in 
rooms fitted with direct piping and some of the fan systems as 





1 I'i'f , , ,','i'i 

M 1 f I ,1 I ' 1 MJ 



well, a large space must be left at floor and ceiling for a circu- 
lation of air, with this system goods may be piled close up to 
ceiling leaving only half an inch for the air to flow into per- 
forations in false ceilings. As the space occupied in height by 
false floor and the space underneath is, in most cases, only one and 
three-fourths inches and that occupied by false ceiling only one 
and one-fourth inches, it is apparent that much space will be saved 
by using this system. After a room is filled with goods and cooled 
down to the correct carrying temperature, no difference in tem- 
perature can be noticed in different parts of the room. No blast 
of air can be felt in any place, a gentle flow from perforations 
only is noticeable, therefore no particular place has more circu- 
lation than another to cause a drying out of the goods. The 



advantages of this system over any of the others may be summed 
up as follows: 

1. A more equal distribution of air, especially when the 
room is filled with goods. Goods in center of room are exposed 
to the same temperature, circulation, etc., as those at sides. 

2. Saving in space, as it allows the room to be filled full 
of goods without leaving large spaces at top and bottom for a 
circulation of air. 

3. \\'here the air is so perfectly distributed and collected 
it is not necessary to circulate such a large volume, saving in 
power and lessening the liability of evaporation of goods. 

The objections which have been offered are of no practical 
consequence. The first one usually mentioned by an inquirer 
is that the space under false floor is likely to collect litter and 
become foul. The author admits that this apparent objection 
for some time kept him from introducing this system to prac- 
tical service, but when once tried, this was found of no conse- 
quence, as the false floor is made in sections, easily handled, and 
it is as easy to raise these and sweep underneath as to remove the 
2x4s or 4x4s generally used to pile goods on. Another ob- 
jection is the supposedly high initial expense. A contract was 
awarded for the construction of this system for a fair sized house, 
in which the cost for air circulating system, including fans and 
motors, did not exceed $20 i)er cubic feet. It will be seen 
that the cost is of very small importance as compared with the 
practical results obtained and the savings in space effected. Those 
who are skeptical about the advantages of forced circulation, 
and of this system in particular, are invited to visit some of the 
plants designed by the author. 

The objections against forced circulation are largely fanciful 
and are not substantialctl when investigated. The idea that goods 
dry out or evaporate ra]Mdly in a nx>m so equipped, has never 
been even sugj::ested by the author's experience, and this objec- 
tion may be dropped without further comment, as this gp-ound 
has been thraslied over before. It is thought by many that a 
forced circulation system is iinntvessary. expensive to install and 
costly to keep in operation. It ir.ay be admitted that forced cir- 
culation is imiiecessary in the same sense that refrigeration was 
unnecessary fifty years ago. People are getting along without 


it because they do not know or understand its advantages. Many 
other applications of machinery are not absohitely necessary, but 
are used for the improved results obtained. If properly designed, 
the cost of equipping a house with an improved system of forced 
circulation need not be much greater than with direct piped rooms, 
for the reason, mainly, that only half or two-thirds as much piping 
is needed, and because of the saving in main pipes by locating the 
cooling coils centrally and blowing the air to and from the room 
with a fan. As to cost of power for operating, this is very small, 
if using the fans specially designed by the author for this pur- 
pose. (Fans for use with air circulating systems should be of 
special construction. This is considered under the chapter on 
"Ventilation.") It is customary to install a half horse power 
motor for handling the air in a 'room of 15,000 cubic feet. The 
actual power necessary is from one-quarter to three-eighths of a 
horse power. As an offset to the cost of operating the fan may 
be placed the great saving in space gained by the use of the fan 
system. In no case is this less than 5 per cent of the space re- 
frigerated, and sometimes will amoimt to over 10 per cent. Even 
if all the objectiolis urged against the system were true, this alone 
is enough to compensate and more besides. When from 5 to 10 
per cent may be added to the earning capacity of a storage house 
without additional cost of operation it means a big increase in the 
tiet profit of the business. 

Not the least of the advantages of the forced circulation 
system is, that during cold w-eather when the ammonia or brine 
is shut off from circulating through the pipes, their frosted 
surfaces are not exposed in the storage room. It is comparatively 
easy to clean the pipes, as they are more accessible than they are 
in any of the direct piping systems. A still greater advantage 
may be gained by using a process invented by the author, which 
consists in placing chloride of calcium above the pipes, so that 
the brine resulting from a imion of the moisture in the air with 
the calcium will drip down over the pipes. (See chapter on 
'' Uses of Chloride of Calcium.") This prevents the formation 
of frost on the pipes at all times, and during cold weather, 
when the refrigerant is shut off, by keeping up the supply 
of calcium, the moisture and purity of the air are under perfect 


That the tendency is toward the adoption of forced circu- 
lation for the best new work cannot be doubted, even by those 
who do not advocate these systems. It cannot be expected that 
they will come into use all at once, but the writer feels justified 
in predicting that ultimately more than half the high grade in- 
stallations will be done under these systems. The present oppo- 
sition comes largely frcMii the "old Hne" people in the business 
who do not like to see changes and improvements made on 
methods with which they have "had good results" for so many 




In discussing humidity and circulation, it has been explained 
how a large portion of the gases of decomposition and impurities 
of various kinds, which are incident to the presence of perish- 
able products in cold storage, are carried by the moisture existing 
in the air, and that when this moisture is frozen on the cooling 
pipes, or absorbed by ^chemicals, the foul matter is largely ren- 
dered harmless. It may now be noted further that even with a 
good circulation and ample moisture-absorbing capacity, there 
will still be some impurities and gases, detrimental to the welfare 
of the stored goods, which have little or no affinity for the water 
vapor in the air, and consequently accumulate in the storage 
room. Ventilation is necessary to rid a refrigerator room of these 
permanent gases. 

This subject of ventilation for refrigerator rooms has been 
very much talked of, but about which really little is known, so 
far as any practical information is concerned. Some of the more 
progressive cold storage managers have given some attention to 
this part of the business, but many of the largest and best known 
houses do not ventilate their rooms at all, except perhaps during 
the winter or spring, when rooms are aired out for the purpose 
of whitewashing. In some cases the change of air incident to 
opening and closing of doors, when goods are placed in storage 
or removed therefrom, is relied on to supply ventilation. This is 
quite inefficient, because goods are mostly stored during two or 
three months, and removed from storage likewise, leaving several 
months when no fresh air of consequence can penetrate to the 
room, except as the doors may be opened for the purpose of 
taking the temperature of the room. Furthermore, this kind 
of ventilation during the warm weather of summer and during 


a large part of the spring and autumn months is worse than no 
ventilation at all. Some storage men even take so radical a posi- 
tion on this matter of opening doors during warm weather, as to 
insist that the door shall not be opened for the purpose of read- 
ing the thermometer. A double window is placed in the door of 
each room, with the thermometer hanging so that it can be read 
from the outside without opening the door. While the author 
has not practiced this method, it seems to be a good idea, and it is 
certainly preferable to ventilating the room through doors which 
open to the outside air. When doors into rooms open into a cor- 
ridor, the evil is partly prevented, but opening the door or win- 
dow of a storage room directly to the outside air when the tem- 
perature outside is materially higher will always result in more 
or less bad effect on the goods, because of the water vapor in the 
warmer incoming air being condensed on the stored goods. 

Another source of ventilation similar in its results to the 
opening of a door or window is that resulting from the leakage 
of air directly into the storage room, through the pores and 
crevices in the walls, around the doors and windows, etc. — leak- 
age of air literally — air that gets in when everything is supposed 
to be closed. The amount is usually imperceptible, but is enough 
in some houses to be a serious detriment to the quality of work 
done. In small houses with large outside exposure and poor in- 
sulation this air leakage is considerable, but in the big refrig- 
erators of several hundred tiiousand cubic feet capacity, and with 
thorough insulation, it is reduced to practically nothing. The 
loss of refrigeration caused by air leakage, while of some im- 
portance, is of small moment beside the bad effects resulting from 
the moisture and impurities brought in by the warm air from the 
outside. The value of prime, tight insulation, as a conserver 
of refrigeration, aside from a matter of keeping out the warm, 
moist air, is discussed in the chapter on "Insulation," but a word 
about windows and doors is properly in line with the present 


Rather than consider what might be a good way of placing 
windows in a cold storage building, their use should be dis- 
couraged. Even with four or five separate glass, divided by air 


spaces, and with all joints set in white lead, the loss of refrig- 
eration is large. It is also very difficult to fit insulation around 
the window frame so as to make a good job ; and even if a pass- 
able job were practicable, the expense of putting in window^s is 
sufficient to condemn their use. The increased fire exposure is of 
some consequence, too, and with the low cost of electric light, 
windows should not be thought of for cold storage work. Barring 
the small amount of heat given off, the incandescent electric lamp 
is an ideal device for lighting cold storage rooms, as the air is 
not vitiated by gases and odors as is the case when using gas, 
kerosene or candles. 

Doors which will shut tight, forming a nearly perfect air 
seal, with a small amount of pressure, have long been wanted for 
cold storage rooms. Most of the ordinary bevel doors, either 
with or without packing on the bevel, will not shut even ap- 
proximately tight; and in operation nine out of every ten stick 
and refuse to open except after many persuasive kicks and 
surges — we all know how it is. The special cold storage doors on 
the market, the author believes to be far above anything else 
in this line, and does not hestitate to recommend them to those 
wanting a door which will prevent air leakage. The prices are 
very reasonable, considering the excellent material and fine work 
put into their construction. The slight additional cost over the 
common door will be quickly saved, by reason of their quick 
action — opening quickly when the fastener is worked. If a door 
is built on the job, the chief idea to be considered in its construc- 
tion is to build a door which is tight at one point all around. It 
is absolutely impossible to make a door fit on a long bevel, but 
the effort is very frequently made. 


Having presented the subject of air leakage, we may as well 
ask how it is caused and why it must be guarded against. It is 
amenable to the same law as gravity air circulation, which was 
explained quite thoroughly in the first part of the chapter on 
*' Air Circulation." When the outside air is very much warmer 
than that of the storage room, the air in the storage room pro- 
duces a pressure on the floor and lower part of the room, by 
reason of its greater weight, and consequently it seeks to escape 


there. If there are openings near the floor where the air can 
flow out, and others at the ceiling or upper part of the room, the 
air will flow in at the top and out at the bottom of the room. 
Reverse the conditions of temperature, and the direction of flow 
of air is also reversed. That is, when the air outside is colder than 
the air of the room, the cold air will flow into the room at the 
bottom and the comparatively warm air of the room out at the 
top. This action is nicely illustrated by noting the air currents 
in a door which is opened into a cold room when the temperature 
is very warm outside. The warm air rushes in at the top of 
door and the cold air of room out at the bottom. In cold weather 
the direction of air flow will be reversed. 

Perfect inclosing walls for a cold storage room would be 
perfectly air tight, as they would be if lined with sheet metal, 
with soldered joints. The interior conditions would then be 
under more perfect control. It is hardly necessary to do this 
(although it has been done in cases of some old time houses), as 
a practically tight job may be had by using the right materials, 
well put on. Air leakage may not be exactly ventilation, but it 
is a kind of ventilation which has given the writer some trouble 
in the past, and does still, consequently the difficulties of operating 
a house with defective insulation and large outside exposure, and 
still turning out first-class goods are very thoroughly appreciated. 


Methods of ventilation which are permissible when applied 
to the work of supplying fresh air to ordinary structures are 
generally dangerous when used to ventilate cold storage rooms. 
The problem in ventilating non-insulated structures is merely 
the supplying of fresh air from the outside without causing a 
marked change in the temperature, and without creating strong 
drafts. Air for the ventilation of refrigerator rooms, during 
warm weather, must be of very nearly the same temperature and 
relative humidity as the air of the room to be ventilated, and free 
from the germs which hasten decay and cause a growth of fungus 
on the products in storage. If a door or window of a storage 
room is opened directly to the outside atmosphere, there will be 
little or no circulation of air into and out of the room when the 
temperature outside and in is about the same, unless the wind 


should be favorable. As we cannot ventilate in this way when 
the air outside is colder than the storage room, on account of 
freezing the goods, and the introduction of fresh air, which is 
warmer than the storage room, is not permissible, for reasons 
already given, the matter reduces itself to not ventilating at all 
during warm weather (which most houses practice) or of prop- 
erly cooling and purifying the air before forcing it into the storage 
room. It will bear repeating that it is positively bad practice 
to allow air from the outside to get into a cold storage room 
during the summer months, also during a large portion of the 
spring and fall months, unless cooled and purified first. The 
fact that we cannot see the moisture deposited in the form of 
beads of water, or floating in the air in the form of fog or mist, 
does not indicate that it is not present. The sling psychrometer, 
described in discussing humidity, will give an accurate indica- 
tion of the result of this unscientific method of ventilating. 


Any natural means of handling air for ventilation is in- 
accurate and inoperative, or it may be positively harmful, except 
under favorable conditions. If depending on natural gravity for 
ventilation it will be guesswork, to a greater or less extent, be- 
cause depending on conditions which vary with the season, tem- 
perature, direction and force of the wind, etc. The late Robert 
Briggs, an authority on ventilation, makes a concise statement 
of the advantages of using fans for ventilation, in his "Notes on 
Ventilating and Heating."* He says : "It will not be attempted 
at this time to argue fully the advantages of the method of 
supplying air for ventilation by impulse through mechanical 
means — the superioritv of forced ventilation, as it is called. This 
mooted question will be found to have been discussed, argued 
and combated on all sides in numerous publications, but the con- 
clusion of all is, that if air is wanted in any particular place, at 
any particular time, it must be put there, not allowed to go. 
Other methods will give results at certain times or seasons, or 
under certain conditions. One method will work perfectly with 
certain differences of internal and external temperature, while 
another method succeeds onlv when other differences exist. 

•Proceedings Am. Soc. Civil Engineers, May, 1881. 


* * * No other method than that of impelling air by direct 
means, with a fan, is equally independent of accidental natural 
conditions, equally efficient for a desired result, or equally con- 
trollable to suit the demands of those who are ventilating/* 


There are two general methods, with some modifications, for 
handling air for ventilation: The plenum or pressure method, 
in which the fresh air is forced into the room; and the vacuum 
or exhaust method, in which the foul air is drawn out. The 
exhaust method is to be avoided for ventilating cold storage 
rooms, for reasons which we shall see presently. With this 
method, sometimes the exhaust steam from an engine is utilized 
to induce a draft of air upward from storage room, by heating 
the air in a stack or ventilation flue connected at its lower end 
with the room to be ventilated. In some cases no provision is 
made for an inflow of fresh air, in which case it will seep in at 
every crack, crevice and pore (by reason of the partial vacuum 
created by exhausting the foul air), bringing a load of moisture 
and germs of disintegration into the storage room. This ex- 
haust steam method is no diflFerent in its result than if a fan 
were placed so as to draw the air out of the storage room under 
conditions which are otherwise the same as described in con- 
nection with the exhaust steam method. Should we provide an 
inlet for fresh air, through proper absorbents, the same law 
would be operative, only to a lesser degree, as a partial vacuum 
must in any case be created before the air from outside would 
flow into the room, tending to the dangerous air leakage already 
fully discussed. 

The plenum or pressure method is by far the best for our 
purpose. The air should be forced into the room by a fan, 
after first properly cooling, drying and purifying it. An outlet 
for the escape of the foul gases which it is desired to be rid of 
should be provided near the floor, as these gases, by reason of 
their greater gravity, tend to accumulate in the lower part of 
the r(X)m. It will be observed that forcing the fresh air in creates 
a pressure inside the room, and if there is any air leakage, it 
will be outwardly from the room — exactly the way we want it to 
go. Having brought our subject to the point where it is found 


that the best way to ventilate is by the use of fans forcing the 
air into the storage room, we will determine what type of fan is 
best adapted to our needs. What is said of fans for ventilation 
is equally true if they are to be used for forced air circulation, 
described in chapter on ** Air Circulation." 


It is admitted by a majority of experts on air moving ma- 
chinery that the disk or propeller wheel type of fan, through 
which the air moves parallel to the axis of fan, is not efficient 
or desirable for work where the air has to travel through a series 
of tortuous air ducts, as in the forced air circulation system for 
cold storage work, or for ventilation purposes where there is 
some resistance. Where any resistance of importance is en- 
countered, the disk fan must be driven at a high rate of speed, 
and at an immense loss of power, to compel it to deliver its full 
quota of air. Another disadvantage of the disk type is the dif- 
ficulty of belting to the shaft, or of getting power to the fan in 
any form, if it is inclosed entirely in an air duct. The disk type 
will therefore be dismissed, and the well known centrifugal, or 
peripheral discharge fan taken up. 

This type of fan draws the air in at its center parallel to 
the shaft, and delivers it at right angles to the shaft at the 
periphery or rim of the fan wheel, the law governing its action 
being the well understood centrifugal force, which is commonly 
illustrated when we see the mud fly from a buggy wheel, or the 
water off a grindstone. The advantage of these fans over the 
disk type is that the centrifugal action set up by the rotary motion 
of the fan is utilized to give velocity to the air in its passage over 
the fan blades. In the selection of a fan for the purpose of forced 
circulation in the storage room, or for forcing in fresh air for 
ventilation, it should be noted that a large, slow running fan 
wheel is very much more economical of power than a small fan 
running at a high rate of speed, both doing the same amount of 
work. The loss of refrigeration, too, in a rapidly moving fan, 
is of consequence, because the air is warmed by impact with 
the blades. The proportion of power saved by the use of a large 
fan running at a slow rate of speed rather than a small fan run- 
ning at a high rate of speed, both delivering the same amount of 


air, is almost phenomenal, and does not seem at all reasonable at 
first view. The volume of air delivered by a fan varies very 
nearly as the speed, while the power required varies about as 
the cube of the speed. That is, doubling the speed doubles the 
volume of air, while the power required is increased eight times. 
We will take a specific case. A 45-inch fan wheel, revolving at a 
speed of 200 revolutions per minute, delivers, say, 5,000 cubic 
feet of air per minute, and requires but one-quarter of a horse 
power to operate it. If the speed is increased to 400 revolutions, 
the volume of air delivered will be only about 10,000 cubic feet, 
while the power required to drive it will be raised to two horse 
power. These figures are theoretical, but within certain limits 
are approximated in practice. 

For use in cold storage work the objection common to nearly 
all the air moving machinery found listed by the manufacturers 
is the seemingly unnecessary amount of metal used in its con- 
struction. The heavy weight of the fan wheels, and the large 
diameter of shaft necessitated by such weight, causes much fric- 
tion on the journals, so that when running at the slow speeds 
desirable for cold storage work, more power is required to over- 
come the mechanical friction than is actually required to move 
the air. 

No doubt the high speeds necessary for some work have 
obliged the manufacturers to make their fans amply strong for 
the highest speeds, consequently they are not economical for the 
slower speeds. It would not be appropriate for a person to fan 
himself with a dinner plate — it would do the work, but would not 
be economical of power. 

Having been unable to find a fan wheel well suited to the 
requirements of cold storage duty, the writer has designed and 
constructed a line of fan wheels especially for slow speeds, which 
are amply strong and capable of moderately high speeds, when 
necessary, but are very much lighter than most fans on the mar- 
ket, and consume proportionately less power in mechanical fric- 


So far we have found out what kind of ventilation is not 
desirable, and have an inkling of what kind would be desirable. 


The question before us now is to properly treat the air before 
introducing it into the storage room, so that it may be fresh — 
i. e.j pure oxygen and nitrogen, without excessive moisture, 
and free from the impurities and germs which may contaminate 
the product which is being refrigerated. 

The free outside air during warm weather, especially in 
the vicinity of our large cities, contains, among many others, 
germs which produce the parasitic plant growth which is called 
mildew or mold. The exhalation from the lungs of the many 
animals and men who inhabit our cities, and the evaporation from 
the dust, dirt and decaying matter of various kinds peculiar to 
the street, render the air a receptacle and conveyor for impurities 
and germs of many species. The species of germs which con- 
cern us are active in proportion to the temperature and humidity 
of the air. In a warm atmosphere which contains much moisture 
they take root and grow rapidly, throwing oflF more germs of 
their kind, which impregnate the air in an increasing ratio as 
the humidity and temperature are increased. The humidity of 
the outside air is not necessarily increased with the temperature, 
but it is always increased to some extent, and as the temperature 
of the outside air rises we must necessarily be more and more 
carelulhow v;e treat and handle the air which we are to use for 
the ventilation of refrigerated rooms. 

It is readily understood why it is necessary to cool the air 
before introducing it into the storage room to at least as low a 
temperature as that of the room to be ventilated, and some cold 
storage managers have ventilated on this basis, thinking that 
this was all that was necessary for successful ventilation. Air 
cooled only to the temperature of the storage room will be 
saturated with moisture at that temperature, and will be in con- 
dition to develop mold rapidly. An improvement on this man- 
ner of handling is to cool the air to be used for ventilation to 
a few degrees (say five or six) below the temperature of the 
storage rooin. The air will then be rendered as dry as that of 
the storage room. This is a good method of ventilation, and 
one which the author has practiced, but it is open to criticism, 
because of the fact that the air is not purified fully at the same 
time it is cooled and dried. If the air is first cooled to several 
degrees below the temperature of the room to be ventilated it will 



be of benefit to the room, if not overdone, but in results will not 
be equal to a system to be described and illustrated further on 
in this chapter. 




Several houses known to the author ventilate by letting the 
warm outside air in ar a point near to the ceiling, directly over 
cooling coils, expecting that the air will be properly cooled and 
dried before it flows into the room itself. The same objections 


are applicable to this system as are applicable to any plan of 
ventilating where the air is cooled only to the temperature of the 
room to be ventilated, because the air will be at the 
saturation point, and will therefore raise the humidity of the 
room, as well as introduce a quantity of germs and impurities. 


If we ventilate by simply cooling the air, the simplest and 
most effective method, as shown in Fig. i, is to take the air from 
as high and sheltered a place as is accessible about the building ; 
draw it down over frozen surfaces in the form of brine or am- 
monia pipes, which may be arranged anywhere along the wall of 
a room, outside of the storage entirely, if more convenient. An 
exhaust fan takes the air from the coils in the ventilating flue 
and forces it into the room to be ventilated, allowing it to escape 
in the neighborhood of the cooling coils, where it will mix with 
the air circulation, and flow into the room through the regular 
channel. It is necessary to provide an outlet for the escape of 
foul air whenever fresh air is forced into the room. This outlet 
should be near the floor, and of about the same area as the inlet 
pipe. A steam coil may be provided beneath the cooling coil 
in ventilating flue, as shown in the sketch, for the purpose of 
melting the frost off the pipes. The casing around the cooling 
coil should, of course, be insulated moderately, as well as the 
pipe leading from it to the storage room, wherever exposed to 
the warm outside air. The size of apparatus necessary for this 
purpose need not be large, as the quantity of air which is gen- 
erally required for the ventilation of storage rooms is quite small, 

"Americus''* mentions a method of washing air for ventila- 
tion, which seems to have advantages. The idea is to draw or 
force air through a body of water or brine by immersing the in- 
take pipe so that the air will bubble up through the liquid. 
This seems quite simple, but when it comes to forcing air through 
a liquid with a fan it is not so simple, as nothing short of an air 
pump will drive air through a pipe submerged as above de- 
scribed, unless the opening from pipe is placed quite near the 
surface of the liquid; in which case the benefit to the air is very 

•In Ice and Refrigeration, July, 1898. 


small. Experiments conducted by the author along this line were 
considered failures. 


Shown in Fig. 2 is what appears as a rather complicated ap- 
paratus, but on investigation it proves to be quite simple. There 
are three parts to this apparatus, as follows : 

First. — The air-washing tank, in which the air flows up- 
ward against a rain of water from a perforated diaphragm above, 
as clearly shown in the sketch. This not only cools the air to the 
temperature of the water, say 55° or 60° F., but it also takes 
out a large portion of the impurities of various kinds. From the 
washing tank the air is passed on, in a comparatively pure and 
cool state, to be still further cooled. 

Second. — The cooling tank, in which the air is cooled to 
several degrees lower temperature than that of the storage room. 
This removes the moisture which holds in suspension the few 
impurities which may have passed the washing tank, the moisture 
being deposited on the frozen surfaces within the cooler. 

Third. — The drying box, into which the air from the cooler 
is passed, and which contains chloride of calcium. This chemical 
is a well known absorber of moisture, what is technically known 
as a deliquescent substance. If moisture of any account passes 
the cooler it is surely stopped in the dryer, which "makes assur- 
ance doubly sure," so far as delivering a pure, dry air is concerned. 
It would be a hardy germ, indeed, that would not succumb to 
the washing, cooling and drying processes of this system of ven- 
tilation, which is as thorough as it well may be theoretically, and 
practically is very effective. 


The volume of air necessary for ventilating a given size of 
storage room can only be estimated, and probably no two storage 
men will agree as to what is a correct quantity. Some say that 
the introduction of a volume of air equal to that of the room 
to be ventilated should take place each day; others twice each 
day ; some even take so radical a view of it as to say the oftener 
the better if the air is properly dried and cooled. This is of 
course true enough, but foul gases which can be gotten rid of 
by ventilation accumulate but slowly in a storage room, and it is 
probable that the introduction of a volume of fresh air, properly 


treated, equaling that of the storai;;e room, twice each week- 
will be ample for the purpose of keeping the room in good con- 
dition, and in most cases once each week may do nearly as well. 
There is much to be developed yet in the direction of ventilation 
of refrigerated rooms, more particularly in the way of some 
method of knowing when a room requires ventilating. Perhaps 
some bright chemist will in time make investigations and ascer- 
tain what the gases are which we must dispose of, and indicate 
some simple method of determining their presence, and in what 

All that has been said about ventilation so far applies only 
to the ventilation of cold storage rooms when the air without 
is warmer than the air of the storage room. We will now give 
our attention to another kind of ventilation that is applicable 
when the air without is at about the same temperature as the 
storage room, or at some degree lower. This will be designated 
as cold weather ventilation, as this term seems to express its 
function perfectly. 


It has long been a well understood fact that products held 
at about 30° F. or higher are more liable to be irtjured in 
cold storage during the cool or cold weather of fall and winter 
than during a long carry through the heated term. Much has 
been said and written about why the old style overhead ice cold 
storages give such poor results during fall and winter, the reason 
assigned being lack of circulation, as the meltage of ice ceases 
when the cool weather comes. This is true: further, the large 
body of ice becomes an evaporating surface, and the dirt and 
impurities which are found in all natural ice, to a greater or less 
extent, have accumulated on the top of this ice, and the evapora- 
tion which takes place carries gases from this miscellaneous mat- 
ter into the air of the storage room, with consequent bad results. 
In some houses this may be avoided by closing the trap doors 
covering circulation flues, but it is seldom done, and in many 
houses it is impossible. 

Now are we who cool our storage rooms with brine or 
ammonia pipes very much better off in this one respect than those 
who have these much despised overhead ice cold storages? Our 
rooms are cooled bv frozen surfaces, on which accumulates the 


evaporation from the goods in store, which, as we have already 
plainly seen, contains much foul matter and impurities. Pre- 
cisely as in the ice cold storages, the cooling surfaces, which ab- 
sorb moisture during warm weather, become evaporating sur- 
faces, and give back to the air of the room a considerable portion 
of the various impurities and germs which have been accumu- 
lated during the warm weather of summer. To make this point 
more plain it may be considered thus : During the period when 
the outside air is considerably warmer than the air of the storage 
room it is necessary to keep some refrigerant at work cooling 
the air within. This is usually done by circulating brine or 
ammonia through pipes and the air of the room is circulated 
in contact with the pipes. When the outside temperature is 
high, more of the refrigerant must be circulated, or its tem- 
perature must be lowered; as the weather turns cooler in the 
fall, less refrigerant, or the same amount at a higher temperature, 
must be circulated, and when the air without reaches the tem- 
perature of the room, the circulation of refrigerant must be 
discontinued altogether. When this is done the moisture on 
the cooling pipes begins to evaporate. This evaporation added 
to that which is given off by the goods themselves soon causes 
the air to be saturated with very impure and poisonous vapors 
which cause the goods to deteriorate very rapidly. 


The influence which the temperature of the refrigerant flow- 
ing in the cooling pipes has on the condition of a storage room 
may be better understood by taking a specific case : A room with 
a temperature of 33'' F. and a humidity of 70 per cent has a dew 
point (temperature at which the air precipitates moisture) of 
25° F. Therefore any cold surface (as a pipe surface), having 
a temperature of 25° F. or lower, will attract moisture when ex- 
posed to the air of the room. If the pipe surfaces are heavily 
coated with frost, as they usually are as cold weather approaches, 
the frost acts as an insulator, and the refrigerant flowing in pipes 
must be at a considerably lower temperature than the air of the 
room, or no moisture is attracted. We have all noted how the 
accumulation of moisture on pipe coils is slower and slower as 
the thickness increases, until finally a limit is reached where no 


more frost will form ; yet owing to the largely increased surface 
the room can be kept at its normal temperature. If pipes are 
badly loaded with frost, sometimes no absorption of moisture will 
take place when the refrigerant flowing in the coils is io° or 15° 
below the temperature of the room. The surface exposed to the 
air of the room, whether in the form of frost or otherwise, must 
be at or below the temperature of the dew point, or no moisture 
will be absorbed. The value of suitable moisture-absorbing sur- 
faces as the cool weather of fall and winter approaches cannot 
be overestimated, as many have found to their sorrow that two 
weeks stay in cold storage under bad conditions in cold weather 
will do more harm to eggs in particular than four months during 
hot weather. 

The remedy for this trouble is found in keeping the air of the 
room from coming in contact with the poisonous frost which has 
been accumulated on the pipes during their period of duty during 
warm weather; or what is still a better way is not to allow the 
frost to accumulate on the pipes at all, by using a device, described 
elsewhere under head of ** Absorbents.'' How to keep the air 
from contact with the frost on pipes is not an easy matter, and in 
case of piping suspended directly in the room it is an impossibility. 

With a system of screens arranged around coils, as described 
in the first part of the chapter on " Air Circulation," trap doors 
may be very easily fitted to the openings and the air circulation 
shut off in this way; but the simplest and best way is to equip 
the rooms with forced circulation, and locate the pipes outside 
of the room entirely. Then it is only a matter of shutting 
off the circulation over coils, or allowing it to continue through a 
by-pass, or if the process described in the chapter on "Uses of 
Chloride of Calcium" is used, the circulation may be allowed to 
continue over coils. It seems quite clear, from what has been 
written, why a storage room gets foul quickly during cool weather, 
and also that the bad conditions may be bettered by cold weather 
ventilation. The harm resulting from the foul evaporation from 
frost on cooling pipes may be obviated by not allowing contact 
between it and the air of room, but the evaporation from the 
products themselves must be taken up by other means when cool- 
ing surfaces are no longer operative. 



By carefully observing conditions a storage room may nearly 
always be kept in prime condition during cold weather by no 
other means than the introduction of fresh outside air at as fre- 
quent intervals as right conditions of temperature and humidity 
will permit. It is quite safe to force in plenty of air which has 
about the same temperature and humidity as the room to be ven- 
tilated. There are few impurities in the clear, crisp air of a 
bright fall day, and many such are available for our purpose in the 
latitude of Minnesota and New York, and a somewhat smaller 
number, perhaps, in the latitude of Iowa or Ohio. It is only 
a matter of handling the free air of heaven understandingly. 
One's impressions, however, will hardly do in judging what air 
is good to use for ventilating purposes. If you have a bright, 
clear day, or, what is still better, a clear cold night, which has 
the appearance of being what you want, get out your sling 
psychrometer and set all guesswork aside. It is frequently pos- 
sible to fill your storage rooms with fine, pure air at a temper- 
ature about the same as that of the room, as early as the latter 
part of October, if you are watching for the opportunity. Pro- 
vide a good big fan wheel, which will handle a large volume of 
air in a short time, and when conditions are right blow your 
rooms full of it. Repeat this whenever the weather conditions 
will permit. 

We may now consider cold weather ventilation under an- 
other condition, viz. : When it is colder outside than inside the 
storage room. Whenever the outside air is 8** or lo'' below that 
of the storage room it is always perfectly safe to introduce it 
into the storage room, after it has been first warmed to the tem- 
perature of the room to be ventilated. That is, it is safe so far 
as introducing moisture or impurities is concerned. If we should 
ventilate in this way continuously our humidity would be low- 
ered to a point where the goods might suiler from evaporation. 
It is necessary, therefore, that observation of the humidity of 
the room so ventilated be taken, so that this kind of ventilation 
may not be overdone. 

The method of getting air into the rooms under these last 
two systems of ventilation is of no special moment, except that 
it be under control, and we have already noted that the only 


good way of handling air was by the use of fans, preferably large 
and of light weight, and running at a slow speed. Where the 
forced circulation is installed, it is sometimes practicable to so 
connect the fans used for this purpose, that cold weather ven- 
tilation may be handled by them; but a separate fan is much 
better and while it seems more complicated it is really simpler to 
operate, because handled independently. When using an inde- 
pendent fan or when using the forced circulation fan for ven- 
tilating, the fresh air mixes with the circulation and is well dis- 
tributed by it to various parts of the room. 

The ventilation of cold storage rooms is not a matter which 
can be safely left to such help as may be at hand, and if good 
results are to be secured "the boss'' should see to it himself. 
Cold weather ventilation, especially, must be handled carefully 
and scientifically or trouble may result instead of benefit. No 
absolute rules can be given for handling ventilation because of 
widely varying conditions, but if what has been written is read 
and studied carefully the subject can be taken up intelligently 
and followed out to its legitimate conclusion. 




Up to about the year 1898 the subject of humidity of cold 
storage rooms was given very little or no attention by cold stor- 
age operators, and no successful means of testing humidity had 
been found for the requirements of refrigerated rooms. About 
the year above referred to the author secured a sling psych rom- 
eter, such as is used at stations of the United States Weather 
Bureau, and made some tests. This instrument is now in gen- 
eral use for the purpose, and is well adapted for obtaining the 
humidity of cold storage rooms. More attention has been given 
to the subject each year, and as it costs practically nothing and 
requires very little time, all houses should make tests to know 
how they stand in this important respect. 

The humidity of a cold storage room under ordinary condi- 
tions depends on the season to a moderate extent, and the con- 
dition of the room, as regards ventilation, in some cases. In 
late fall or winter, especially, if air is taken directly into the room 
from the outside, the humidity will be low. As cool weather 
approaches, the tendency is for the humidity to rise, and unless 
kept down by ventilation or by the use of absorbents, serious 
consequences are sure to follow. 

To enable us to thoroughly understand the meaning of rela- 
tive humidity, as it is called, we will study a few extracts from 
'^Instructions to Voluntary Observers."* Humidity is consid- 
ered on a decimal scale, with 100 the saturation point of the air, 
at which it will hold no more water vapor, and o the point at 
which air contains no moisture whatever. The various percent- 
ages between these points is a degree of humidity relative to 
these two extremes, or relative humidity. The quotations below 

*l8sued by the United States Weather Bureau, Washington, D. C. 


are not contained in the recent issue of instructions, but are from 
the issue of 1892, which is now superseded by that of 1897. 


The air contains vapor of water, transparent and colorless like its 
other gaseous components. It only becomes visible on condensing to fog 
or cloud, which is only water in a fine state of division. The amount is 
very variable at different times, even in the vicinity of the ocean. The 
amount of moisture that can exist as vapor in the air depends on the tem- 
perature. There is a certain pressure of vapor, corresponding to every 
temperature, which cannot be exceeded; beyond this there is condensation. 
This temperature is called the temperature of saturation for the pressure. 
When the temperature of the air diminishes until the saturation tempera- 
ture for the vapor contained is reached, any further fall causes a con- 
densation of moisture. The temperature at which this occurs is called 
the dew point temperature of the air at that time. The less the quantity 
of moisture the air contains, the lower will be the temperature of the dew 
point. For different saturation temperatures, the weight of vapor, in 
grains, contained in a cubic foot of air is as follows : 

Temperature Weight in a 

of Saturation, Cubic Foot, Grains. 

Degrees F 

o 0.56 

10 0.87 

20 1.32 

30 1.96 

40 2.85 

50 4.08 

60 574 

70 7.98 

80 10.93 

90 14.79 

100 19.77 

The air is never perfectly saturated, not even when rain is falling; 
neither is it ever perfectly dry at any place. Relative humidity expresses 
relative amount of moisture in the air only as long as the temperature of 
the air remains constant. For this reason relative humidity is an imperfect 
datum. At a low temperature even a high relative humidity represents 
a very small amount of vapor actually in the air, while a low relative 
humidity at a high temperature represents a great deal. 

The most important law relating to above concise statements, 
and one which, if carefully noted and applied, will make all work 
in humidity easily understood, is best expressed thus: The ca- 
pacity of air for moisture is increased with its temperature. 
Strictly speaking, air has no capacity for moisture, the water 
vapor being simply diffused through the air, after the nature of 
a mechanical mixture. For all practical purposes, we may regard 
it as being' absorbed by the air, and it is usually so treated. 

At a temperature of 40® F., air will hold in suspension more 
water vapor than at any lower temperature (see table) ; and 
when the difference is as much as 10° F., the difference in the 


amount of moisture the air will hold is very considerable. To 
illustrate : Air which is saturated with moisture at 30° F.» when 
raised in temperature to 40** F., then holds but 68 per cent of 
its total capacity. 


There are two kinds of instruments in use for determining 
humidity, hygrometers and psychrometers. The hygrometer de- 
pends on the expansion and contraction of some substance, as a 
human hair, in the presence of more or less moisture in the air. 
The hair used is fastened at one end, the other end passing 
around a pulley, to which is fastened a pointer, which moves 
over a graduated arc as the hair changes its length. The scale 
reads from o to 100. The chief advantage of these instruments 
is that results are obtained at once, the reading corresponding 
to the percentage of saturation or relative humidity; but these 
instruments are affected by changes of temperature, and shocks 
or vibration materially affect the reading. Further, they are 
more expensive in first cost, and not so convenient to use, as they 
must hang for some time in the room to be tested, while with the 
sling psychrometer, described in another paragraph, an observer 
can pass from room to room, getting observations in less than two 
minutes in each room, needing but one instrument and making 
all observations at practically the same time. 

A psychrometer is simply two thermometers mounted on a 
frame ; the bulb of one being covered with muslin so as to retain 
a film of water surrounding it. The working of this instrument 
depends on a law which may be roughly expressed, as "evapora- 
tion carries off heat." The evaporation of water from the bulb 
incased in muslin, known as the wet bulb, cools it somewhat* 
depending on how dry the air surrounding it may be. The dif- 
ference between the reading of the wet bulb thermometer and 
the reading of the dry bulb thermometer, when compared with 
reference to a prepared table, gives the relative humidity of the 
air at the time of making the observation. Psychrometers are of 
two kinds, stationary and sling. 

The stationary psychrometer is essentially like the sling 
psychrometer, both depending on the same principle. The sling 
instrument is more compact and provided with a handle for 


FIG. I. — 


whirling, while the stationary instrument is 
intended to be fastened against the wall, or on 
a post, the muslin covering the wet bulb being 
connected by a porous cord with a reservoir 
of water, to keep the supply of water con- 
tinuous. This is essential, as it takes some 
little time to obtain a correct reading with 
this pattern of instrument. For this reason 
it is open to the same objections as the hygro- 
meter. Also, after short use the muslin cov- 
ering the wet bulb, and the cord feeding 
w:u< r to it, become clogged with solid matter and 
fungous growth affecting its accuracy. At any tem- 
perature below 32° F. this instrument is useless, as 
the water will freeze in the cord supplying the muslin 
on I lie wet bulb, and the muslin becomes dry in con- 
st <|uence. 

For practical, accurate and quick results at any 
temperature there is no instrument so reliable and 
convenient as the sling psychrometer, preferably of 
the i)attern known as Prof. Marvin's improved psy- 
chrometer, shown in Fig. i. This is a standard 
Weather Bureau instrument, and when used in con- 
nection with the tables of humidity published by the 
lintcau, any needed results may be obtained with a 
fair degree of accuracy. The sling psychrometer, as 
illustrated, consists of a pair of thermometers 
mounted on an aluminum plate, one higher than the 
other, the lower having its bulb covered with a small 
sack of muslin. At the top, the frame or plate sup- 
porting the thermometers is provided with a handle 
for whirling, this handle being connected by links to 
the plate, and provided with a swivel to allow of a 
snux^th rotary motion. The bulb of the lower ther- 
niDTneter is wet at the time of making an observation, 
the muslin serving to retain a film of water, surround- 
ing and in contact with what is known as the wet bulb 
of the psychrometer. The muslin should be renewed 
from time to time, as the meshes between the threads 


will gradually fill with solid matter left by the evaporation of the 
water and the natural accumulation of dust from the air. The 
muslin in this condition will neither absorb nor evaporate the 
water readily. 


To make an observation dip the muslin-covered bulb in a 
small cup or other wide-mouthed receptacle containing water. 
Whirl the thermometer for ten or fifteen seconds, then dip the 
wet bulb of the psychrometer into the water again. Whirl again 
for ten or fifteen seconds, stop and read quickly, reading the 
wet bulb first. Repeat once or twice, noting the reading each 
time. When two successive readings of the wet bulb agree very 
nearly, the lowest point has been reached. Dip the wet bulb only 
after the first whirling, as this is done only to make sure that 
the muslin is thoroughly saturated with water. If the water 
used is of nearly the same temperature as the room, correct read- 
ings are sooner obtained. If the psychrometer and water are at 
a much higher temperature than the air of the room, it will take 
a proportionately longer time to reach a correct reading, but the 
accuracy will not be impaired, if sufficient time is allowed for the 
mercury to settle. It is very important that the muslin-covered 
bulb should not become dry in the least; it should be saturated 
with water during the full time of observation. There will be 
no difficulty in getting accurate readings down to 29° F., as 
indicated by the dry bulb. At about this temperature, and with 
the wet bulb at about 27° F., ice will form on the wet bulb and 
cause the psychrometer to become somewhat erratic in its be- 
havior. Readings below 30° F. are therefore very difficult to 
obtain, and it is only after repeated trials that results may be ob- 
tained in some cases. By dipping the instrument in water at a 
temperature near the freezing point and then rapidly whirling it 
results may usually be obtained. A stationary hygrometer is en- 
tirely inoperative at any temperature below 32° F., as the water 
in the fountain and cord will freeze solid. The sling psychrometer, 
according to Prof. Marvin, its originator, is supposed to be as 
accurate when the wet bulb is covered with ice as when covered 
with water, but this is not borne out by the author's personal ex- 


perience. There is something to be desired in the way of further 
information on this point. 

It is difficult to describe the proper movements for whirling 
the sling psychrometer, a little practice being the best instructor. 
The handle is held in a horizontal position, the frame mounting 
the thermometers revolving around the pivot, after the manner 
of the weapon with which David slew Goliath, and from which 
our moisture-tester gets the easy part of its name. A high rate 
of speed is unnecessary, a natural, easy motion of the forearm 
or wrist being all that is required. When stopping the psychrom- 
eter the arm should follow the thermometer from the highest 
point of the circle of rotation, whereby the radius of the path of 
the psychrometer is increased, and the momentum overcome. 
The stopping can be accomplished in a single revolution, after a 
little practice. The psychrometer will come to rest very nicely 
by simply allowing the arm to stand still, but the final revolution 
will be quite irregular and jerky. 

In making observations in a storage room, the psychrometer 
should be held as far from the body as convenient, and toward 
the direction from which the circulation comes — the observer 
standing to the leeward, as it were. In some cases it is necessary, 
or advisable, to step slowly back and forth a few steps, and the 
observer should turn his head from the direction of the psychrom- 
eter so that his breath will not affect the reading. In reading a 
thermometer, read as quickly as possible, and do not allow the 
breath to strike the bulb. It is a common practice with the 
author to hold his breath while reading a thermometer. It is 
unnecessary to caution against allowing the psychrometer to 
strike any object while whirling. In case it should, the observer 
will have $5 worth of experience, but no psychrometer. 

The following short table needs no explanation further 
than has been already given. It will cover most cases in cold stor- 
age observations. It was not intended for cold storage work, 
being a part of the regular humidity tables published by the 
Weather Bureau. The full set of tables can be had by addressing 
the chief of the Weather Bureau, Department of Agriculture. 
Washington, D. C. They are published in pamphlet form, along 
with tables giving dew point temperatures. Observers must 
W'Ork out the small fractions for themselves, if they think neces- 



sary, but results within the limits covered by the table are near 
enough for practical purposes. 


Difference between dry and wet thermometers (/— 













































































































































































































































































































































































It is of no use to test for moisture unless having the means 
to control it, any more than a thermometer would be of use 
unless the means of regulating temperature were at hand. Hu- 
midity can be controlled by ventilation, already discussed, and 
the use of absorbents, which are considered in the following 




The use of absorbents in cold storage rooms has been com- 
mon since the industry was in its infancy; their use originating, 
no doubt, from an appreciation of the fact that the air of a stor- 
age room quickly became too moist and impure to do the work 
of preservation perfectly. When absorbents and ventilation are 
applied to refrigerator rooms they practically have one duty in 
common — that of purifying the air. Ventilation purifies by fur- 
nishing pure air which displaces the foul air; absorbents by at- 
tracting the moisture, and with it the impurities of the storage 
room. But while ventilation is largely for the purpose of forcing 
out the permanent gases or impurities which have little affinity 
for moisture, absorbents are for the purpose of taking up the 
moisture and the germs and impurities which are absorbed by it. 

Active absorbents can be made to perform duty in absorb- 
ing the moisture which is usually condensed on the cooling coils, 
as illustrated in one style of the antiquated overhead ice cold 
storages, called Prof. Xyce's system. In this system the ice is 
supported above a water-tight sheet iron floor which forms the 
ceiling of the storage room, the air of the room being cooled 
merely by contact with this cold metal surface, which is cooled 
by the ice above. The moisture given off by the goods in storage, 
and that resulting from air leakage was taken up by an absorbent, 
chloride of calcium being the chemical mostly in use for this pur- 
pose. It was applied by suspending it in pans at the ceiling of 
the room, or in some cases on the floor under the goods. Prof. 
Nyce's system gave good results years ago in competition with 
the Jackson, Dexter, McCray, Stevens, etc., systems of overhead 
ice cold storage, which low temperatures, and the improved sys- 
tems of air circulation now in use have rendered obsolete to a 


greater or less extent. Mention is made of this system not as 
recommending it, but to show the possibilities of absorbents in 
drying and purifying storage rooms. 


The two chemical absorbents in general use for taking up 
moisture and the impurities from cold storage rooms are chloride 
of calcium and lime (either unslaked or air-slaked, or in the 
form of whitewash). (See chapter on "Keeping Cold Stores 
Clean.*') Occasionally waste bittern from salt works is used, 
but the active principle of bittern is chloride of calcium. Or- 
dinary quicklime has the property of absorbing moisture and 
impure gases from the air, and is used in very much the same 
way as chloride of calcium; that is, it is placed around the 
room on trays or pans. Lime, however, has very little ca- 
pacity for moisture as compared with chloride of calcium, and 
when exposed to the air it will simply air-slake, which means 
that it will absorb moisture enough from the air to disinte- 
grate into the form of a powder. L.ime in this form is known 
as air-slaked lime, and is used to a large extent in storage 
rooms. Air-slaked lime as it comes from the lime house will 
absorb very little moisture, but it gives off minute particles 
of lime which have a good effect in preventing the growth of 
fungus, which we have already fully discussed. Air-slaked lime 
is usually applied by spreading on the floor of the room, between 
the 2x4s (which are used at the bottom of each pile of goods), 
10 the depth of an inch or more. This must necessarily be done 
when the goods are piled, and consequently its efficiency is very 
low when the cool weather of fall comes. This defect has been 
overcome by scattering fresh air-slaked lime through the rooms 
so as to create a cloud of lime dust, but this is objected to be- 
cause it musses up the cases. A better way of using lime is in 
the lump form — quicklime — which can be placed around the top 
of the room in trays or pans and renewed from time to time 
through the season. 


Chloride of calcium is the most vigorous absorbent (or 
drier, as it is called) which we are discussing. It is the same 


salt of the metal calcium as common salt (chloride of sodium) 
is of the metal sodium. Both have a strong affinity for water, 
but chloride of calcium is much the more energetic of the two. 
Where, in a moist air, common salt simply attracts enough mois- 
ture to become damp, chloride of calcium will absorb enough 
water to lose its solid form entirely, uniting with the moisture 
of the air to form a solution or brine. The strong affinity of this 
salt for water has been utilized for the purpose of drying and 
purifying refrigerator rooms, and in this capacity has been a 
general favorite for years. The most primitive method of ap- 
plying it is to place it in a simple iron pan, allowing the brine to 
run off into a pail as fast as formed. A better way is to support 
the calcium on a screen of galvanized wire, with a galvanized 
pan below for catching the brine. This allows of a free circula- 
tion of air around the calcium. This apparatus should be sus- 
pended near the ceiling of the room, one end slightly higher, to 
allow the brine to run off into a galvanized iron pail, supported 
at the low end of the pan. Galvanized iron is specified because 
black iron rusts badly when exposed to the air. (In the chapter 
on "Uses of Chloride of Calcium" a complete description of the 
uses of this material and illustrations of methods of applying are 

Do not in any method of using chloride of calcium evaporate 
the water from the brine and use the salt over again. The im- 
purities will stay in the salt to a large extent, which is quite 
harmful, and the calcium has at least lost its value as a purifier, 
to a large extent. The quantity of calcium necessary depends 
on the conditions under which it is to be used, but in any case 
it is safe to use much more than the author saw in use in one 
eastern house. A room about 30x50 and about fourteen feet 
high had the refrigerant shut off, and the room was in rather 
bad condition as to moisture, etc. In each end of the room a pail 
was placed, on which rested a wire screen, with perhaps ten or 
fifteen pounds of chloride of calcium on it. Electric fans were 
playing on the calcium, which was doing its best, but it seemed 
"like trying to dip the sea dry with a clam shell." This room 
should have had at least two drums (about 1,200 pounds) at work 
in it to do it justice. 




Chloride of calcium is a substance which is known in chem- 
istry as a deliquescent salt, which term means that it will become 
liquid by the absorption of moisture from the air. It is obtained 
as a by-product in the preparation of ammonia from ammonium 
chloride and lime ; in the preparation of potassium chlorate from 
calcium chlorate and potassium chloride; in the ammonia-soda 
or Solvay process, and in the manufacture of carbon dioxide or 
carbonic acid gas. The greater portion of the commercial prod- 
uct comes from the waste bittern from the salt works, and the 
Solvay process for the manufacture of soda. 

The capacity of chloride of calcium for water depends 
largely on the temperature at which the solution from which it 
is prepared is evaporated, and to the presence of a greater or less 
percentage of impurities (chloride of magnesium, chloride of 
sodium, gypsum, sulphates, etc.), some of which possess com- 
paratively little or no value as absorbents. Commercial chloride 
of calcium, as generally prepared, holds about 25 per cent of 
water, and it will absorb in addition to this, when exposed under 
average conditions in cold storage rooms, somewhere from one- 
half to nearly its own weight of water, depending on humidity of 
the air, temperature, method of applying, etc. It is the most 
active moisture absorber, or drier — as it is sometimes called — 
in common use, and because of its low price ($10 to $15 per ton), 
it has come into general use for many purposes. In general 
character, common salt (chloride of sodium) and chloride of 
calcium are similar, both having strong affinity for moisture. 

It is a well known fact that cold storage rooms are purified 
to a large extent by extracting the water vapor which is held in 



suspension by the air contained in the rooms. The water vapor 
contains a greater part of the foul gases, germs of decay, etc., 
which are given off by the goods, or introduced into the rooms by 
admitting impure moist air from the outside. The water vapor 
laden with these impurities is disposed of in mechanically refriger- 
ated cold storage rooms by being frozen on the cooling pipes. Be- 
cause of the strong affinity of chloride of calcium for moisture, it 
can be utilized to accomplish the same duty in moisture absorbing 
and purification which can be accomplished by the refrigerating 
pipes. It has been in use for years for this purpose; the nat- 
ural ice cold storage houses having used it largely before the 
advent of the refrigerating machine. When used in a room 
cooled by air circulated directly from the ice, it is of very little 
service except during very cold weather, because such a room 
is held at a positive humidity by the air circulating continually in 
contact with the moist surface of the melting ice. 

The possibilities in the use of chloride of calcium for mois- 
ture absorbing are well illustrated in the system of overhead ice 
cold storage originated by Professor Nyce. (See chapter on 

The success of this system depends on chloride of calcium 
as its only agent for moisture absorbing and purification, and 
proves conclusively its value for the purpose, and those who 
are operating mechanically refrigerated houses can take some 
ideas from this old system which will assist them through the cold 
weather of fall and winter, when they are obliged to discontinue 
the flow of refrigerant through the cooling pipes. When this 
becomes necessary, the frost on pipes must be promptly cleaned 
off (which is at times impossible, owing to the stock of stored 
goods in the room), or the frost will throw off water vapor which 
is laden with impurities which have been absorbed from the air 
of the room. The result is easy to foresee. The air becomes 
moist and foul, and goods stored in such an atmosphere deter- 
iorate very rapidly. The remedy for such a state of things is to 
expose to the air of the storage rooms a large quantity of chloride 
of calcium ; or, what is better still, this condition can be made im- 
possible by preventing the formation of frost on pipes by the 
application of chloride of calcium by a process invented by the 
author, which will be described further on. 




The methods of applying chloride of calcium to the work of 
moisture absorbing are numerous, but the devices illustrated and 
described here have been found to do well and will fit almost any 
case that may come up. Fig. i is a cheap, simple way of sup- 
porting the calcium near the ceiling of room. It is best to 
support the calcium near the ceiling, as the space is less valuable 
and the moistest air is to be found there. The pan or trough of 


galvanized iron, shown in the sketch, should be inclined toward 
the outlet, so that the liquid calcium will flow off into a recep- 
tacle as fast as formed. The pan is usually suspended over the 
alley-way between goods, so that it may readily be refilled as 
required. These pans may be of any size and shape desired, 
corresponding to the space which they will occupy, but in plac- 
ing them in the room plenty of space should be left on the sides 
for the free access of air. The pan shown in Fig. 2 is an im- 



provement on the first, in that the calcium is supported on a wire 
screen, several inches above the pan below, allowing a free flow 
of air around the calcium, exposing a greater surface to the 
action of the air. The liquid dripping from above covers the 
pan beneath with a film of brine, and the air in contact with this 
brine will give up its moisture to some extent, resulting in a 
more dilute brine and, consequently, greater economy in the con- 
sumption of the calcium. In other words, a pound of the cal- 
cium used in the device shown in Fig. 2 will absorb more mois- 



ture than the same quantity used in the device illustrated in Fig. 
I. The general explanation of proper method of using, given in 
connection with Fig. i, is equally applicable to Fig. 2. These 
pans should be constructed of galvanized iron throughout, as 
they are exposed intermittently to the action of the chloride and 
the dry air outside when they are out of service ; and, as tlie cal- 
cium will keep them moist a long time, the action of the air in 
connection with this moisture will cause them to rust badly. Any 



iron surface continually covered with calcium brine will rust 
very little — no more, probably not as much, as it would if ex- 
posed to the atmosphere under ordinary conditions. 

The device shown in Fig. 3 is a more positive and powerful 
arrangement for drying the air of storage rooms than either of 







FbR l/1^ or CflLCiUM CHLOfl. 




the two described. The chloride is placed in a tank or box on 
wire screen shelves, as shown, and the air forced or drawn 
through the box by an exhaust fan, which may be placed on the 


inlet or outlet end, as may be most convenient. The moist air 
should be taken from the top of the room to be dried, and con- 
ducted to the bottom of box, the dry air to be taken out of 
the top of box and discharged at the opposite end of the 
room. In this way the moist air comes first in contact 
with the liquid calcium, or brine, which lies at the bottom of the 
box. As the drip from the top shelves drops from one shelf 
to another, always in contact with the air moving upward, it 
becomes more and more dilute. It will be seea therefore that 
the air which is moistest comes first in contact with the dilute' 
brine at bottom of tank, and last with the dryest calcium at the 
top of box. This results in a greater economy in the use of cal- 
cium, and gives a more perfect drying effect. The devices shown 
in Figs. I and 2 are much slower in their action, because depend- 
ing on the ordinary air circulation in the room to bring the air 
containing the mixture in contact with the calcium. 


A better method of utilizing chloride of calcium than those 
described has been designed and thoroughly tested by the au- 
thor. Claims fully covering this process have been allowed by 
the patent office at Washington, and it has been put in service in 
a large number of refrigerating plants. In this system the 
calcium is made to perform two distinct duties, that of keep- 
ing the pipes free of frost during warm weather, and during cold 
weather, that of maintaining the air of the storage room at its 
correct degree of humidity, at the same time maintaining it 
in a pure state. The process is applicable to any of the me- 
chanical systems of refrigeration wherein a refrigerant is cir- 
culated through coils of pipe, or to any system where the rooms 
are cooled by refrigerated metal surfaces. A smaller amount of 
surface is required to do a given refrigerating duty when the 
pipes are clean than when the frost is allowed to accumulate 
on the pipes, and the economy of a device which will keep 
the refrigerating pipes free of frost at all times will be ap- 
preciated by any person familiar with the business, as it is well 
known that frosted pipes are insulated partly, the degree to 
which they are insulated depending on the thickness of the coat. 
We have ^Ir. E. T. Skinkle's ("The Boy") opinion that this is 



probably about as the square of the thickness of the frost. Mr. 
John Levey states that the efficiency of the coils is increased from 
15 to 25 per cent by this process. The author's process consists 
simply in placing a quantity of chloride of calcium in proximity 
to the refrigerating surfaces, so that the brine resulting from a 
union of the moisture in the air with the calcium will drip over 
the refrigerating pipes. After passing down over the pipes, the 
brine falls onto a water tight floor, which is provided with drip 

-CHuoRion or Calcium 

OoouMq C01LJ 


connections to the sewer, or the brine may be collected and used 
as a circulating medium in the system. This effectually and con- 
tinually disposes of the brine which contains the moisture and 
impurities from the air of the storage room, therefore contami- 
nation from this source is impossible. The apparatus illustrated 
in Fig. 4 is a simple and effective manner of applying the cal- 
cium, although it can be applied in any other manner to produce 
the desired result ; as in case of ceiling coils the calcium may be 
placed directly on the pipe. The film of brine, covering the pipes, 


which is produced in this way, practically prevents the formation 
of frost, and the cooling surfaces of the pipes are therefore 
maintained at their maximum efficiency at all times. The eco- 
nomical advantages of this process are great, the cost of installing 
the apparatus very small, and the expense for calcium not large. 

The disadvantages of the system are very few, if any. The 
chief one which has been suggested so far is that the chloride of 
calcium brine trickling over the pipe surfaces would cause the 
pipes to rust. Rather than rust the pipes, the brine has a cleaning 
and protective effect, and coils which have been equipped with 
this process show freer of rust after being in service for a few 
weeks than when first fitted up. It is generally conceded by 
those who have observed carefully that the most favorable con- 
dition for rusting of iron is alternately wetting and drying in the 
presence of a free circulation of air. When the pipes are coated 
with a film of brine, no corroding action of consequence will take 
place, because the air cannot have free access to the surface of 
the pipes. 

The expense for chloride of calcium has also been cited as an 
objection to the process. When it is considered that it is only 
necessary to supply about the same weight of the salt as of the 
frost to be kept off the pipes, it will be seen that expense for this 
salt is of very small importance. The estimated weight of frost 
which will accumulate on the pipes during the season in a room 
of 20,000 cubic feet is about 2,000 pounds. The amount will vary 
greatly with the* season of the year, product stored, and whether 
room is opened often or not, but above figures will cover average 
conditions. The cost of calcium as compared with the economy 
which results from maintaining clean pipes at all times is of small 
moment, amounting to only a very small percentage of the sav- 
ing effected by maintaining the refrigerating surfaces at their 
maximum efficiency at all times. 

To show the possibilities of this process, combined with the 
system of forced air circulation designed by the author and fully 
described in the chapter on " Air Circulation," the following is 
quoted from a letter received from a gentleman using these sys- 
tems. He says: 

A remarkable thing is the small amount of cooling surface required. 
I put eleven coils, sixteen and one-half feet long, fourteen pipes to the 


coil, in the coil room, and I am indeed surprised to find that with this 
system I only need one of these coils, containing 231 feet of i-inch pipe, 
brine entering at 14° F. from our ice tank. 

This statement refers to the cooling of a room of about 
20,000 cubic feet capacity to a temperature of 33° F. This 
means that a lineal foot of i-inch pipe is cooling about eighty- 
five cubic feet of space, with brine at an initial temperature of 
14° F. 

Naturally, this process, like all others, would have some limi- 
tation as to its application; and this limitation is found when a 
temperature of about 10° F. is reached. It has been used suc- 
cessfully in a room where the temperature was carried at 12° to 
15° F., but when tested in a freezer at a temperature of 8** F. 
the action of the calcium was very slow and the process inopera- 
tive. At a temperature of 30° F. the action is rapid, and no 
difficulty was experienced in keeping a coil of sixteen i-inch brine 
pipes, one above another, practically free of frost. 


The preparation of chloride of calcium for use is attended 
with some very disagreeable features, unless a person has had 
experience and knows the nature of the material to be handled. 
Some of those who have used calcium have been discouraged 
from using it again by the hard labor required to put it in shape, 
and the wetting of floors it causes when carelessly handled. For 
the benefit of those who have never handled this salt, and for 
those who have experienced difficulty in its preparation, the fol- 
lowing directions are given, which if adhered to, will make the 
preparing of calcium for use as simple a matter as any of the 
routine work about a cold storage warehouse. 

Chloride of calcium in the commercial form comes from the 
manufacturers in the form of a solid cake, encased in an air tight 
sheet iron jacket. These jackets are known as drums. They are 
simply ordinary black sheet iron of a very light gauge, and are of 
no value, and when removed from the calcium may as well be 
thrown away at once. The drums of calcium weigh about 600 
pounds each, and, though heavy, are easily rolled or trucked, 
and require very little space for storage. 

For use, the calcium needs to be broken into lumps, ranging 
in size from ten pounds downward. This is for convenience in 


handling and for the purpose of exposing a fair amount of sur- 
face to the action of the air. For breaking the calcium select a 
clear floor space, where nothing can be injured by the moisture, 
which soon collects on the small pieces which are scattered in 
breaking. Pound the drum with a sledge hammer, using strong, 
vigorous blows, working around the drum and do not strike 
twice in the same place (see Fig. 5), as this tends to pulverize 
the calcium too much for easy handling and for air drying pur- 
poses, though for brine making the finer the calcium is broken 
the better. After pounding the drum outside thoroughly, stand 
it on end and take off the top of the drum by prying it out with 
an old ax or chisel. It is then an easy matter to cut down the 
side with an ax, when the sheet iron jacket may be easily re- 


moved. Any large pieces needing further breaking may be re- 
duced in size without much trouble by striking on the flat side. 
It is a very simple and easy matter to break the calcium in this 
way. An active man will prepare and place a drum in an hour 
or two. 

The calcium begins absorbing moisture from the air very 
quickly, especially in warm, humid weather, and for this reason 
when a drum is once broken into, it should be disposed of as 
quickly as possible. The small pieces which fly about when the 
cake is being broken should be swept up promptly to prevent 
making a muss ; some dry sawdust, scattered over the place where 
the cake was broken, will be found useful in taking up the mois- 
ture which accumulates. As before stated, chloride of calcium 
is of a similar character to common salt, and aside from the dis- 


agreeable property of making everything damp with which it 
comes in contact, and keeping it so for some time, is entirely 


A non-congealable liquid is used in refrigeration as a sec- 
ondary or circulating medium for absorbing the cooling effect 
of an expanding gas, and applying it directly to the work to be 
done. This non-congealable liquid has been in the past usually 
a solution of common salt in water; but of late chloride of cal- 
cium has come into use quite generally for this purpose. Prob- 
ably the chief reasons why it has not come into general use be- 
fore to the entire exclusion of common salt brine, are : That it 
is, or has been, much more expensive in first cost ; that it is more 
difficult to prepare and handle the solution, and also that it can- 
not be obtained everywhere like common salt. Chloride of cal- 
cium possesses positive advantages over common salt for brine 
making. It is now used by many of the leading engineers in the 
business, and where once adopted, has not, in a single instance 
known to the writer, been discarded for common salt. As the 
use of the so-called brine coolers have made the brine circulating 
system more desirable, and the brine system is now in favor for 
most purposes, the proper -understanding of chloride of calcium 
and its use should be a part of the information possessed by 
every engineer connected with the business. 

Those who have written on the subject of refrigerating ma- 
chinery and refrigeration, have had very little to say regarding 
the merits of the two different salts for brine purposes. Most 
of the information formerly available relates to common salt 
brine, which is a sort of tacit recommendation for its use; but 
brine and brine making in a general way have until recently been 
given very little attention by writers on refrigeration. In con- 
nection with some investigations bearing on the process for pre- 
venting frost on refrigerating pipes already described, the author 
has collected all the available information on the general subject 
of chloride of calcium, and all facts obtainable show that calcium 
brine has important advantages over that made from common 

The manufacturers or venders of chloride of calcium claim 
that it is a better conveyor of refrigeration and that "it does not 



eat up the pipes like salt." These claims are, roughly speaking, 
true, and if the reasons why had been given, the claims would 
have more weight with engineers. The author's reason why 
chloride of calcium brine will not rust refrigerating pipes has 
already been given in connection with the explanation why cal- 
cium brine trickling over the pipes in the frost preventing proc- 
ess will not rust the pipes. Probably ordinary salt brine will 
not corrode the pipes very much more on the inside, but wherever 
it has access to the exterior of the pipes in contact with air, as 
from a leaky joint, the corrosion and deterioration are much more 
rapid than where calcium brine is used. It is probable that the 
impurities encountered in common salt are responsible to a great 


extent for the peculiar rotting action which it has in some cases 
on cast or wrought iron or steel. Calcium also contains damag- 
ing impurities at times. Figs. 6, 7 and 8 illustrate the "pitting" 
or corrosion of pipe when using salt brine, and freedom from same 
when chloride of calcium brine is employed. The surfaces of pipes 
moistened by common salt brine, are, owing to varying condi- 
tions causing a tendency to dry at one season of the year and 
become moist at another, subject to the action so favorable for the 
corrosion of the metal. Calcium brine will not, under any con- 
ditions to be met with in cold storage rooms, give up enough 
water to lose its liquid form, so will not allow of a drying out on 
the pipes except after a considerable length of time has elapsed. 



Without the aid of chloride of calcium the present perfect 
types of brine coolers would not have been possible. Now the 


brine cooler is recognized as a feature of nearly all up-to-date 
cold storage plants, and in many ice factories the brine for freez- 
ing is cooled in a brine cooler. The saving of space, low cost, 


and perfection of interchange of temperature between the am- 
monia and the brine, make the brine cooler an ideal device. Op- 
erating engineers appreciate the saving to them in care of looking 


after a large number of expansion valves scattered throughout 
the plant. 

Obviously calcium brine has a great advantage over common 
salt brine at temperatures below zero F. Common salt brine at 
its maximum density will freeze at about 7° below zero F., while 
calcium brine can be made which will not freeze at 50° below 
zero F. It will be seen that where a temperature of zero F. 
or lower is required in cold storage rooms with brine circulation, 
calcium brine only can be used. For a given minimum brine 
temperature a less dense brine of calcium can be used than of 
common salt, giving more conducting power per pound. The 
advantages of this are that a given weight of calcium brine can 
be made to convey more units of refrigeration than the same 
weight of salt brine, saving in the weight and amount of brine 
to be circulated. Chloride of calcium brine has the advantage 
of not being liable to deposit crystals in the pipes should the 
temperature drop below normal, and there is practically no dan- 
ger of freezing if reasonable care is used in its preparation. Ref- 
erence to the subjoined table shows that calcium brine has an 
ultimate freezing point of about 54° below zero F. with a 30 
per cent solution. A 25 per cent solution is all that is required 
in almost any work, and for most purposes a 20 per cent solution 
is amply dense. For ice making, where a brine temperature of 
10° to 20° F. is carried in the tank, a brine ranging from 12 to 
18 per cent is all that is required. The brine must, of course, 
be strong enough to prevent ice forming on the expansion coils, 
so that the temperature of the expanding ammonia must largely 
regulate the density of the brine. It will be noted from the table 
that a very strong solution of chloride of calcium has a much 
higher freezing point than a more dilute brine. A brine contain- 
ing too much calcium is therefore to be guarded against. The 
most common test for brine is the salometer, a hydrometer scaled 
from zero of pure water to 100 per cent or more, which is about 
the point of a saturated sohitibn of common salt brine. A Baume 
hydrometer scale can also be used for ascertaining percentage of 
calcium. The per cent of calcium given in the table represents 
the total per cent, and as the commercial fused chloride of cal- 
cium already contains about 25 per cent of water, more of this 
article will be required for a given quantity of water than is 



Stated in the table. The small sub-table of approximate practical 
proportions of the commercial calcium and water, for brine of 
a required test, will be found useful in the making of brine. (See 
the following page.) 

The preparation of brine, using chloride of calcium, is a 
simple matter but somewhat slower than where common salt is 


used, owing to the much smaller surface exposed to the action of 
the water. It is difficult to break calcium by hand into small 
grains like salt, therefore it dissolves comparatively slowly. The 
simplest way is to put the correct proportion of calcium and 
water in a barrel or barrels, and stir slowly with a piece of gas 
pipe to facilitate solution. Another method is to put the correct 
quantity of calcium and water in the brine tank, and start the 
pumps running. The circulation of water in contact with the 
surface of the calcmm is what is necessary. Others use a steam 
pipe lead directly into the brine tank or other receptacle. This 
is perhaps the more rapid way, but it is not desirable, from the 
fact that the solution may not be at the correct degree when com- 
pleted, because of the indefinite amount of steam necessary to 
effect a solution. It is best to have the solution amply strong at 
first, as it can be readily reduced by adding water in sufficient 
quantity. If the live steam method is used, a good proportion to 
put into the brine receptable is six pounds of the calcium to each 
gallon of water, or a drum to each loo gallons. This will make 
a very strong brine which can be diluted as required. In testing 
brine it is necessary to have the solution at a temperature of 60** 
F., as any variation from this temperature will cause error in the 
test. The brine is easily warmed or cooled to the correct degree. 
A glass hydrometer jar (see Fig. 9) is useful, as supplying a 
convenient tall vessel, and the scale on the hydrometer can be 
read more accurately than wnth a piece of gas pipe with a cap on 
one end, which some use. 

The following table is the one referred to above for the making 
of calcium brine and will be found of practical value : 


Pounds Chloride 

of Calcium 

Degrees Salome- 
ter. fe'^^F. 






fused) to One Gal- 

6o« F. 

Degrees F. 

lon of Water. 








— 2 




— 9 





4'i 1 

1 ^'^ 















6 . 


























1. 015 





- -5 

— .9 









— 1-4 









— 1.9 









— 2.4 









— 3.0 
















— 4.3 









— 5.1 








~ §•§ 







-18. 1 

— 6.8 





1. 103 








1. 112 








1. 121 









1. 131 




— II.O 




1. 140 









1. 150 



- 7.5 





1. 159 









1. 169 



h 1.7 






1. 179 


— 1.4 






1. 189 

















— 11.6 






1. 219 
































1. 261 






































— 9-7 




4- 2.8 






NoTB. — The -|- sign denotes temperature above zero, the — sign, 
temperature below zero. 

A part of the preceding tables and some of the informa- 
tion contained therein has been kindly supplied by the manu- 
facturers of chloride of calcium, and while the tables have been 
proved inaccurate, they will answer for practical purposes. 





Eggs are the most important product now taken care of by 
cold storage methods, both as regards aggregate value and bene- 
fits to the community. They are also among the most difficult 
products to successfully refrigerate. Over five years ago the 
author estimated the total value of eggs under refrigeration for 
safe keeping at about $20,000,000 annually for the United States 
alone. Statistics show that the consumption of eggs doubles 
about every five years. Therefore the value of eggs annually 
cold stored in the United States at this time (1904) cannot be 
very far from $40,000,000. Appreciating the importance of the 
industry and the lack of accurate information available, the author, 
in the interest of a better understanding and dissemination of 
knowledge on the cold storage of eggs, communicated with quite 
a large number of individuals and companies, requesting that 
they give full answers to a printed list of questions sent them. 
The result has been most gratifying ; nearly one-half of those writ- 
ten to acknowledged receipt of the inquiry, and more than one- 
half of this number gave fairly complete replies to the questions 
submitted. Considering the fact that the inquiries were regarded 
by some as being of a rather personal nature, the proportion of 
managers sending replies in full is large. Several gentlemen 
were frank enough to say that personal considerations prevented 
them from giving any information; others gave guarded or 
partial replies. In the main, however, storage men have shown 
themselves willing to give information and exchange ideas. 

The list of inquiries sent out covers the subject quite thor- 
oughly, and divides it into six different parts, namely, tempera- 
ture, humidity, air circulation, ventilation, absorbents and pack- 
ages, with three separate questions relating to each. To the data 


so cheerfully furnished by others is added information from the 
author's experience and practice with such explanation of theory 
and practice as may seem necessary to a clear imderstanding of 
the principles of successful egg refrigeration. It is hoped that 
those who are new to the business may obtain valuable informa- 
tion from these collected data, and that those with experience may 
derive some benefit in the way of a review, and possibly pick up 
some new ideas as well. 


Questions regarding the correct temperature of egg rooms 
have been asked repeatedly of storage men who have been in the 
business long enough to be looked to for advice, the same person, 
perhaps, giving a different answer from time to time, as his 
ideas change. At present there is no temperature on which a 
large majority of persons can agree as being right, and as giving 
superior results to any other. The claims made by the advocates 
of different temperatures wall be considered, to determine, if 
possible, what degree is giving the best results in actual practice. 

The three questions relating to temperature were written 
to draw out opinion as to the right temperature, the lowest safe 
temperature, and what deleterious effect, if any, the egg sus- 
tained at low temperatures, which did not actually congeal the 
egg meat. The three temperature queries were : 

First. — At what temperature do you hold your rooms for 
long period egg storage? 

Second. — What temperature do you regard as the lowest 
limit at which eggs may be safely stored? 

Third. — What effect have you noticed on eggs held at a 
lower temperature? 

All the replies received contained answers relative to tem- 
perature, and by a very small majority 32° F. is the favorite 
temperature for long period egg storage. Some few, 33° F. and 
34° F., with a few scattering ones up to 40° F. Under the freez- 
ing point, none recommended a temperature lower than 28° F., 
and for a very obvious reason, this being near to the actual freez- 
ing temperature of the albumen of a fresh egg. A very respect- 
able minority say a temperature ranging from 30° F. to si'' F. 
is giving them prime results; and several recommend 30° F. 


straight, and say they should go no lower. In recent years there 
has been a decided tendency among storage men to get the tem- 
perature down near the safety limit, but many houses are so 
poorly equipped that they are unable to maintain a uniform low 
temperature below 33 "^ F., without danger of freezing eggs where 
they are exposed to the flow of cold air from coils. A house 
must be nicely equipped to maintain low temperatures with 
safety. More houses would use temperatures under 32"^ F. were 
they able to without danger to the eggs. A very successful 
eastern house issued a pamphlet in 1892. At that time they 
maintained a temperature of from 32"^ to 34° F. in their rooms. 
In sending out this little book during the winter of 1897-98 a post- 
script was added, as follows: "This pamphlet was published 
in 1892, when our plant was started. Since that time all first- 
class cold storage houses have lowered their temperatures ma- 
terially." No better illustration than this can be cited to show 
the tendency of the times. These people now use a temperature 
of 30° F. for eggs. 

Most of the replies received contained answers to the second 
question, and the greater portion state this as being about 2** F. 
lower than that recommended for long period storage. It is 
presumed that these two degrees are allowed as leeway, or margin 
of safety, for temperature fluctuations. Some state that eggs 
cannot be safely held below 32** F., but give no reason why, while 
two or three say a temperature of 27° F. will do no harm to 
eggs in cases. One reply states that eggs held in cut straw at 
25° F. for three months showed no bad symptoms. It has never 
been made clear how the package can be any protection against 
temperature, when the temperature has been continuously main- 
tained for a length of time sufficient to allow the heat to escape ; 
and we know that eggs will positively freeze at 25** F., as proven 
by experiments mentioned in another paragraph. 

The answers to the third question were few in number, but 
cover a wide range. The scarcity of data on this point indicates 
that few have experimented with eggs at temperatures ranging 
from 25° F. to 30° F. Some say: "dark spot, denoting germ 
killed" ; others, "white gets thin" ; others, "eggs will decay more 
quickly"; or, "they will not 'stand up' as long when removed 
from storage." It is also claimed that "yolk is hardened or 


'cooked' when temperature goes below 32° F." Some answers 
state a liability of freezing if eggs are held in storage at a tem- 
perature below 32° F. for any length of time. 

As far as possible, we will dig out reasons for the claims 
made by advocates of both high and low temperatures, both 
having equal consideration. Taking 29° F. or 30° F. and 38° F. 
or 40° F., as representing the lowest and highest of general prac- 
tice, we will see what is claimed by each; and also the faults of 
the other fellow's way of doing it, as they see it. Those who are 
holding their egg rooms at 40° F. say it is economical, that the 
eggs keep well, that the consistency of the egg meat is more 
nearly like that of a fresh egg after being in storage six months, 
than if held at a lower temperature. As against a low temper- 
ature they say : A temperature of 30° F. is expensive to main- 
tain ; the yolk of the egg becomes hard and the white thin, after 
being in store for a long hold ; and that when the eggs are taken 
from storage in warm weather it will require a longer time to 
get through the sweat than if held in storage at a somewhat 
higher temperature, resulting in more harm to the eggs. Some 
claim that the keeping qualities are impaired by holding at a 
temperature as low as 30° F., and others note a dark spot, or 
clot, which forms in the vicinity of the germ, when eggs are held 
below 33° F. Against this formidable array of claims, the low 
temperature men have some equally strong ones,- although fewer 
in number. They say: "There is very much less mildew, or 
must, at 30° F. than at temperatures above 32° F. ; the amount 
of shrinkage or evaporation from the egg is less ; an egg can be 
held sweet and reasonably full at this temperature from six to 
eight months." This last claim is a broad one, and comparatively 
few houses are turning out eggs answering to this description. 

The following, relating to high temperatures, is quoted from 
a letter written by one of the best posted men in the business, who 
has spent much money and time on experiments, and studied the 
question for years. He says : "A temperature of 40** F. is very 
good for three months' holding, but if they run over that, it is 
more than likely the eggs will commence to cover with a white 
film, which grows the longer they stand, and finally makes a 
musty egg." This gentleman advocates a temperature of 30° F. 
for long period holding. It should be noted that the high tem- 


perature men ig^nore entirely the effect of high temperatures on 
the growth of this fungus, spoken of above as a white film. The 
worst thing about most storage eggs is the taste caused by this 
growth (usually called mildew or mold), which results in what 
is commonly called a musty egg. To enable us to understand the 
validity of these claims made by the 30° F. people, it will be 
necessary for us to ascertain the conditions which are favorable, 
and also the conditions which are unfavorable for the propagation 
of this growth of fungus, which has given storage men so much 
trouble, ever since cold storage was first used for the preserva- 
tion of eggs. 

Heat and moisture are the two conditions leading to its 
rank growth, and the opposite — dryness and cold — will retard 
or stop the growth entirely. In moist, tropical countries many 
species of this parasite grow, while in the cold, dry regions of 
the north its existence is limited to a single variety. The causes 
leading to a grow th of the fungus on the outside of an egg are not 
far to seek. It feeds on the moisture and products of decom- 
position which are being constantly given off by an egg, from 
the time it is first dropped until its disintegration, unless im- 
mersed in a liquid, or otherwise sealed from contact with the 
air. This evaporation not only takes moisture from the egg, 
but carries with it the putrid elements from the egg tissue, re- 
sulting from a partial decomposition of the outer surface of the 
egg meat. Conditions of excessive moisture and the presence of 
decaying animal or vegetable matter, together with a moderate 
degree of heat, are essential to the formation of fungus of the 
species which are found growing on eggs in cold storage. As 
the heat and moisture are increased, the growth of fungus will 
be proportionate. Furthermore, we all understand that heat 
hastens decomposition, and the partial decomposition of an egg 
results in a growth of the fungus, as before explained, when 
conditions of temperature and humidity are favorable. If the 
temperature is low, this growth is slow ; for instance, if eggs are 
held at a temperature of 30° F. in an atmosphere of given hu- 
midity, the growth of fungus is less rapid than if held at any 
temperature higher, with the same per cent of humidity. As our 
subject merges into humidity here, the reader is referred to what 
is said in regard to this under the head of "Humidity/* 


Returning to the objections urged against low temperatures, 
we will see what damage is claimed from the use of a tem- 
perature of 29° to 30° F. The objections are : Liability of freez- 
ing; germ is killed; white becomes thin; yolk is hardened, and 
eggs will not keep as long when removed from storage. Some 
interesting results are obtained from experiments made by the 
author. Half-rotten or "sour" eggs freeze at temperatures just 
a trifle under 32° F. Fresh eggs freeze at 26® to T.y'' F. In 
testing eggs which had been held in storage for several months, 
it was noted that the freezing point had been reduced from 1° 
to 2° F. An ^%^ which is leaky will freeze at 2° to 3° higher 
temperature than one which is sound, probably owing to the 
evaporation from the uncovered albumen resulting in a lower 
temperature. The freezing point of eggs, as above, is under- 
stood as being the degree at which they begin to form ice crystals 
inside. Of the replies received touching on the freezing point of 
eggs, nearly all agree with above experiments. The "dead germ" 
theory the author has never been able to locate in fact, having 
never seen anything of the kind in eggs held as low as 28° to 2ff 
F. for several weeks' time ; nor in eggs held at 30° F., or a trifle 
under, through the season. As only two or three mention having 
noted this result, it would seem that some local conditions, and 
not low temperature, were responsible. 

The matter of the white becoming thin when eggs are 
held at low temperatures has some bearing ; in fact, any (t^% held 
at a cold storage temperature for a long carry will show this 
fault, to a certain extent, especially if cooled quickly when stored, 
or warmed suddenly when removed from storage. It is the au- 
thor's opinion that a difference of 4° to 6® F. in carrying tem- 
perature will not be noticeable in its effect on the albumen of an 
cg&5 2ind as to the effect of a low temperature on the ^%% yolk, 
it has been demonstrated that any temperature, which will not 
actually congeal the albumen, will not harm the yolk of an ^^;g. 
There is a slight tendency, in this case, to a similar effect to that 
produced by a low temperature on cheese; that is, causes it to 
become "short" or crumbly. 

In regard to a low temperature ^%% not keeping as long when 
removed from storage, it has been the experience of the author 
that no difference was noted between eggs put out from storage 


and the current receipts of fresh eggs, so far as any complaint 
or objection was concerned, the ^gs being shipped in all di- 
rections, in all weathers and subject to many different conditions. 
A test was also made, by placing three dozen of eggs, which had 
been carried in storage at a temperature of 28° to 30° F. for five 
months, in a case along with three dozen fresh eggs. After three 
weeks no pronounced change was noted in either, both showing 
considerable evaporation as a result of exposure to the dry fall 
atmosphere. They were exposed to the temperature of the re- 
ceiving room, fluctuating from 50*" F. to 80° F. The ^gs from 
storage went through a "sweat," while the fresh were not sub- 
jected to any such trial As most eggs are consumed inside of 
three weeks after being removed from storage, this would seem 
like a good practical test of the vitality of a low temperature 
egg, A mere matter of economy between holding a room at 
40° F. and from 29° to 30 "* F., while readily appreciated and ad- 
mitted, seems of very small importance, when a positive advan- 
tage can be obtained by carrying eggs at the lower temperature; 
and a difference of from 4° to 5° F. would be scarcely worth con- 

An advantage of low temperature, not yet mentioned, is the 
increased stiffness, or thickness, of the white of the egg while in 
storage, holding the yolk in more perfect suspension. When 
eggs are held at a temperature of 36° F., or above, for any period 
longer than four months, the yolk has a decided tendency to rise 
and stick to the shell, causing rotten eggs, known as "spots." It 
is usually understood that the yolk settles ; but, being of a fatty 
composition, it is lighter than the albumen, and rises instead. 
If the albumen is maintained in a heavy consistency, the yolk 
is retarded from rising, and held in a more central position. . It 
was long a practice with storage men to turn eggs at least once 
during the season, to prevent the above trouble, and some recom- 
mend it even now; but the practice has been generally aban- 
doned with the advent of low temperatures for egg storing. 

When eggs are put in cold storage they should not be cooled 
rapidly. The effect on the egg tissues is bad — they should have 
time to rearrange themselves to the changed temperature. This 
is especially true where eggs are placed in storage in extreme 
warm weather. Sudden warming is also detrimental to the wel- 


fare of an egg, for a similar reason to above. The most notice- 
able effect of either is a thinned albumen. If this process of 
cooling and warming could be accomplished slowly (which is 
not always practicable commercially), a well kept storage egg 
would come out of storage with nearly the same vitality it had 
when fresh. 


Information on the subject of humidity, as applied to the 
cold storage of eggs, is very meager. Not more than a dozen 
of the replies received in answer to the list of inquiries sent out 
contain information on the three queries under the head of hu- 
midity. Considering the amount of talk we have all heard, with 
dry air as a subject, this scarcity of knowledge is rather sur- 
prising. Those who have had experience with cold storage work 
and the products handled are well aware that an essential for 
good results in egg refrigeration is a dry atmosphere in the egg 
room; but just how dry, very few are able to give even an ap- 
proximate estimate. Very likely if a cold storage man is asked 
in regard to it, he will reply that an egg room should be "neither 
too moist nor too dry." What this "happy medium" is, that will 
not shrink or evaporate the eggs badly, and yet keep down the 
growth of fungus to a minimum, is what all are striving for, and 
very few have the means of knowing when this point is reached. 
A few years ago a prominent commission man, in conversation 
with the author, speaking of storage eggs, said : "You storage 
men are between the devil and the deep sea. You always shrink 
'em or stink 'em"; meaning that eggs which were held long in 
storage would show either a considerable evaporation or a radical 
"musty" flavor. To some extent this is true, but with a pene- 
trating circulation, careful ventilation and a judicious use of 
absorbents (all of which are considered under their proper heads) 
eggs can be, and are, turned out of storage without this strong, 
foreign flavor, and with little evaporation or shrinkage. 

The questions relating to humidity were written with a full 
understanding of the scarcity of information on the subject, 
and were designed to locate, if possible, those who were making 
tests of air moisture, and get opinions on the correct humidity 
for a given temperature. The following are the queries : 


First. — What tests, if any, have you made of the dryness 
or humidity of your egg rooms ? 

Second, — WTiat per cent of air moisture do you find gives 
the best results at the temperature you use? 

Third. — What instrument do you use for testing air moisture? 

The first and third questions are practically the same, the 
latter being written simply to make the query more plain and 
indicate whether an instrument or some other test was used for 
determining air moisture. Four houses reporting are using the 
dry and wet bulb thermometers ; the others are using hygrometers 
of French or German make. 

The answers to the second question vary greatly ; some also 
giving the actual testing humidity of their rooms and their opinion 
of a correct degree as well. From 70 to 80 per cent of humidity 
is the test of nearly all reporting, and of the rooms tested by 
the author, nearly all show a similar humidity, with one occa- 
sionally going as high as 85 per cent, and some as low as 65 
per cent. Two answers recommend a humidity of 65 per cent, 
and one a humidity of 60 per cent, with a temperature of 30° 
to 32° F. Others hold that their testing humidity of 70 to 80 
per cent is correct. 

Under the head of 'Temperature," it is stated that: "If 
eggs are held at a temperature of 30° F. in an atmosphere of a 
given humidity, the growth of fungus is less rapid than if held 
at any temperature higher with the same per cent of humidity." 
By referring to the table on page 168 we see that a cubic foot 
of air, when saturated at a temperature of 40° F., contains 2.85 
grains of water vapor, while at 30° F. it contains but 1.96 grains, 
or only about two-thirds as much as at 40° F. 

The same holds true with any relative humidity, the same 
as when the air is saturated. Take, for instance, air at a tem- 
perature of 40° F., with a humidity of 75 per cent, then a cubic 
foot of air holds 2.14 grains of water vapor per cubic foot; and 
at a temperature of 30° F., with the same relative humidity, it 
would hold but 1.47 grains. This great difference in the amount 
of moisture contained in the air at different temperatures, and 
still having the same relative humidity, has as radical an effect 
on the growth of fungus as does the difference in temperature. 
This is no mere theory, as the writer has demonstrated it, to his 


own satisfaction, at least, during several seasons' observation. 
If it is hoped to keep down the growth of fungus in a temperature 
of 40° F. by maintaining an atmosphere with a lower relative 
humidity, the result is a badly evaporated egg, which loses its 
vitality and value very rapidly when held in storage for a term 
exceeding three or four months; the white becomes thin and 
watery, with a strong tendency to develop "spot" rotten eggs. 
As the fullness or absence of evaporation is of only secondary 
consideration to their sweetness, when eggs are tested by buyers, 
it is necessary to prevent this trouble if the eggs turned out from 
storage are to be considered first-class. 

From the foregoing it seems clear that to turn out sweet 
eggs at a temperature of 40° F. it is necessary to maintain a 
lower relative humidity than at any temperature lower, and the 
result cannot fail to be as described. The author has already 
given a summary of the replies to the questions relating to hu- 
midity, which are few in number, and not very complete. A 
little is better than nothing, however, and by comparing his own 
data with the results obtained by others, and paying careful at- 
tention to their opinions, the following table of correct humidity 
for a given temperature in egg rooms has been compiled. There 
are no data on the subject in print, so far as known, and no 
claim for absolute accuracy is made in presenting this first effort 
in that direction, but as the figures are taken from actual re- 
sults, no great mistake can be made by depending on them. The 
percentages of humidity given are modified, to some extent, by 
the intensity and distribution of the air circulation employed : 


Temperature Relative Humidity, 

In Degrees F. Per Cent 

28 85 

29 83 

30 80 

31 79 

32 75 

33 74 

34 70 

35 68 

36 66 

37 64 

38 61 

39 59 

40 56 



A vigorous and penetrating circulation of air must be main- 
tained in a cold storage room for eggs if good results are to be 
insured, and the importance of this condition is quite generally 
appreciated. It is also a fact that a strong, searching circulation 
will do much to counteract defects in a cooling apparatus, or wrong 
conditions in the egg room in some other particular. 

The reason why a vigorous and well distributed circulation 
of air in an egg room will give superior results over a sluggish 
or partial circulation may not be readily apparent. A circulation 
of air is of benefit in combination with moisture absorbing capacity 
in the form of frozen surfaces or deliquescent chemicals. Stirring 
up the air merely, as with an electric motor fan, without pro- 
vision for extracting the moisture, is of doubtful utility, and 
may, in some instances, prove positively detrimental, as it is 
liable to cause condensation of moisture on the goods, or walls 
of storage room, instead of its correct resting place — the cooling 
coils and absorbents. Let us see how the circulation of air in 
a storage room operates to benefit its condition. 

Under head of " Temperature," we have seen that the evap- 
oration from an egg contains the putrid elements resulting from a 
partial decomposition of the egg tissues, and that the air of a 
storage room carries them in suspension. It is probable that 
these foul elements are partly in the form of gases absorbed in 
the moisture thrown off from the egg; and if, therefore, this 
moisture is promptly frozen on the cooling pipes, or absorbed by 
chemicals, the poisonous gases and products of decomposition 
are very largely rendered harmless. This is also true of the 
germs which produce mold and hasten decay, which are ever 
present in the atmosphere of a storage room, being carried to a 
considerable extent by the water vapor in the air, along with 
the foul matter of various kinds referred to. If the vapor laden 
air surrounding an egg is not removed and fresh air supplied 
in its place, the air in the immediate vicinity of the egg becomes 
fully charged with elements which will produce a growth of 
fungus on its exterior, affecting and flavoring the interior — ^the 
flavor varying in intensity, depending on how thoroughly im- 
pregnated with fungus-producing vapor the air in which the 
egg is kept may be. In short, then, circulation is of value because 


it assists in purifying the air. It should be kept up so that the 
air may be constantly undergoing a purifying process to free it 
from the effluvia which is always being thrown off by the eggs, 
even at very low temperatures. 

The questions bearing upon circulation contained in the 
list of inquiries sent out by the author are as follows : 

First. — In piping your rooms what provision was made for 
air circulation? 

Second. — What difference in temperature do you notice in 
different parts of the same room? 

Third. — Do you use a fan or any kind of mechanical device 
for maintaining a circulation of air in the rooms? 

More answers were received on this subject than on the 
subject of humidity, but not exceeding one-third contained prac- 
tical replies to all three inquiries. Several of the answers con- 
founded circulation with ventilation, as before alluded to. The 
first question, in particular, was badly neglected, indicating, no 
doubt, that no provision was made for circulation in a majority 
of cases. The common device in use for causing air to circulate 
more rapidly over the cooling coils, when they are placed directly 
in the room, is some form of screen, mantle, apron, false ceiling 
or partition. Many of these have been put up after the house 
has been in operation for some time, and are very crude affairs, 
applied in all conceivable combinations with the pipe coils. In 
some cases canvas curtains, or a thin wooden screen, have been 
suspended under ceilijig coils with a slant to cause the cold air 
to flow off one side, and with surprising improvement to the 
room, considering the simplicity of the device. Forced circula- 
tion with a complete system of distributing air-ducts is coming 
into general use, as the merits of this way of producing circula- 
tion are better understood and appreciated. 

The second question was answered more generally, but that 
some of the answers were mere guesses, or statements made 
without testing, is very evident, as they state that no difference 
was noticed in different parts of the same room. With open 
piping or gravity air circulation, this is an impossibility — it is 
only possible with a perfectly designed forced circulation system. 
In contrast to this claim some answers state a difference in tem- 
perature of as high as 4° to 5° F., but most answers show a 


difference of i° to 2'' F.; a few of >4° to 1° F.: and, still 
others, as before stated, none at all. A marked variation of tem- 
perature in different parts of a room, while in most cases caused 
by defective circulation, is due sometimes partly to location of 
room as to outside exposure, proximity to freezing rooms, char- 
acter of the insulating walls, etc. An egg room placed over 
a low temperature freezing room will show more variation be- 
tween floor and ceiling than when located over another egg 
room, conditions being otherwise the same. Where this ar- 
rangement occurs, and the egg rooms are operated on a natural 
gravity air circulation system, eggs may be frozen near the floor, 
when a thermometer hanging at the height of a person's eyes 
would read 30° F. or above. Even with the very best insulation, 
the result of this very common arrangement is a defective cir- 
culation and more or less variation in temperature between floor 
and ceiling. 

In reply to the third question, about a dozen state that they 
are using some form of mechanical forced circulation. The ad- 
vantages of this method are discussed quite fully elsewhere in 
this book. About double this number are using the small electric 
fans. These also have been treated in the discussion of mechan- 
ical air circulation in another chapter. 

As air circulation is a somewhat neglected subject, and 
comparatively few have experimented enough to have positive 
opinions, based upon practical experience, regarding the merits 
of different devices and methods, some of the more prominent 
and successful ones are illustrated and discussed elsewhere in this 
book. (See chapter on "Air Circulation.") 


The introduction of a large volume of fresh air is not es- 
sential for the purpose of purifying rooms in which eggs are 
stored, because the accumulation of permanent gases in an egg 
room is quite slow, comparatively (as in rooms where well ripened 
fruit is stored) : but a small supply of fresh air continuously, or 
at regular intervals, is of much benefit. 

The questions referring to ventilation contained in the letter 
of inquiry sent out by the author are as follows : 

First. — What plan do you pursue in ventilating egg rooms? 


Second. — Under what circumstances and how often do you 
ventilate ? 

Third. — How often do you consider it advisable to make a 
complete change of air ? 

Outside of a bare dozen, the replies on this much-talked-of 
subject were of no value whatever for our purpose. Most of 
those answering do not ventilate; many others get their ventila- 
tion through the opening of doors ; some ventilate through an ele- 
vator shaft, by opening doors at top and bottom, etc. Only three 
or four were properly cooling and drying the air before intro- 
ducing it into the egg rooms. One successful storage manager 
says that: "It is trouble enough to take microbes, bacteria, 
moisture, etc., out of one batch of air" (meaning the air in his 
rooms at the beginning of the season), without adding to his 
troubles by sending in more air loaded down with the same 
mischief makers. As pointed out in the chapter on "Ventila- 
tion," unless the air to be used for purifying the rooms is itself 
first cooled and purified, this man's idea is perfectly correct. 
Ventilated egg rooms will, however, turn out eggs which are in 
every way better than from rooms not ventilated, other conditions 
being equal. Eggs from ventilated rooms are clearer and stronger 
bodied (albumen thicker) than from non-ventilated rooms. 

No accurate data have yet been established regarding the 
volume of fresh air which is advisable to use for ventilating egg 
rooms, but it is a simple and inexpensive matter to supply enough, 
and too much cannot be used if it is first properly dried and 
purified and brought to about the same temperature as that of 
the storage room. Ordinarily it is unnecessary to ventilate egg 
rooms until filled with goods and closed for the season. After 
a short time (two to four weeks) begin ventilating, as the accu- 
mulation of gases commences at once as soon as the rooms are 
permanently filled and closed. Ventilate in small quantities and 
for several hours at a time once or twice a week, rather than in 
large quantities less often. 

For a discussion of the principles involved and mechanical 
details of this subject see chapter on "Ventilation." 


The letter of inquiry sent out by the author contained three 
questions referring to absorbents, written with an idea of ascer- 


taining the coating used for the walls of a storage to the greatest 
extent; what absorbent was the favorite, and in what manner 
applied. The questions are as follows: 

First. — Do you use an absorbent or purifier in your egg 
rooms ? 

Second, — In what way do you use or apply them ? 

Third, — Do you paint or whitewash? What kind and how 
often applied? 

The most common wall coating in use for egg rooms is plain, 
every-day whitewash, in various proportions of lime and salt. 
Several recommend one part of lime and one of salt. This makes 
a very good whitewash, giving a firm, hard surface, but unless 
some method of blowing warm, dry air through the rooms is 
feasible, it will dry very slowly, which is likely to cause it to have 
a mottled appearance instead of the pure white which gives a 
storage room such an attractive appearance. A better propor- 
tion for ordinary cold storage work is two parts of lime and 
one of salt. This mixture will dry faster, and will give a white 
surface which will not easily rub or flake off. There are many 
formulas for good whitewash, some of them so complicated as 
to be impracticable; but plain lime and salt, with perhaps the 
addition of a little Portland cement, will be good enough for our 
purpose. See chapter on "Keeping Cold Stores Clean" for de- 
tails of whitewash making, etc. ; also chapter on "Uses of Chloride 
of Calcium" for application of this material, also chapter on 


Eggs are continually giving off moisture from the time they 
are first dropped by the hen until they disintegrate, unless sealed 
from contact with the air, and we can therefore never hope to 
keep them in cold storage for several months without their losing 
some weight by evaporation. To prove that eggs must evaporate, 
the following experiment was tried by the author in his early 
experience: An ordinary 30-dozen egg case was lined with tin, 
with all joints carefully soldered. The eggs were then placed in 
the fillers in the tin lined case in the usual w.^y, and an air-tight 
tin cover soldered on, forming a hermetically sealed package. 
After about sixty days' stay in an ordinary refrigerator the* tins 


were unsoldered. The result noted was peculiar and startling. 
The inside of the tins was dripping wet, and very foul smelling, 
and the eggs were all rotten. This same experiment was tried 
by a friend, working independently and without knowledge of 
the author's experiment. He used an ordinary fruit jar, with 
screw top fitting onto a rubber ring. His results were similar. 
In addition this gentleman packed some eggs in flour in a fruit 
jar, otherwise under the same conditions as the other experi- 
ment. The eggs packed in this way were all found to be in good 
condition when the jar was opened, as the moist evaporation 
from the eggs had been taken up by the flour. These experi- 
ments prove beyond a doubt that an tgg must evaporate con- 
tinually, and they prove further that the eggs must be surrounded 
by some medium which will absorb this evaporation. 

In the chapter on "Air Circulation" it is explained how the 
air is best circulated so as to remove the moisture and impure 
gases from the vicinity of the goods. This must be done, other- 
wise the fillers and package containing the eggs would shortly 
be in as bad condition as the fillers in the experiment just men- 
tioned. The theory and explanation of the other conditions in 
the storage room necessary for successful egg refrigeration have 
also been taken up under the various heads. We will now look 
into the requirements of the package containing the eggs while 
in cold storage. 

The questions contained in the letter of inquiry relating to 
the egg package are as follows : 

First. — What egg package have you found to turn out the 
sweetest eggs? 

Seccmd. — Have you used any kind of ventilated egg case, and 
with what results? 

Third, — Have you ever used open trays or racks, and wuth 
what results? 

As many different people have experimented with different 
packages, hoping to get something which would turn out per- 
fectly sweet eggs, with little evaporation, the replies received to 
the questions relating to packages are interesting, and many 
contained information valuable as data. The favorite package 
is the ordinary 30-dozen egg case, made of whitewood, using 
medium weight hard calendared fillers. The term whitewood 


is usually meant to include either poplar, cottonwood or bass- 
wood, but two or three other varieties of wood, not so well known, 
are designated as white wood. Basswood is by some not placed 
in the whitewood list, but the best authority known to the author 
says that basswood is as properly a whitewood as poplar or south- 
ern whitewood. Poplar and cottonwood are most in use for 
storage purposes, and many insist that basswood is objectionable 
becaue of its liability to ferment or sour and cause tainted or 
musty eggs. All kinds of cases have been in storage in the house 
operated by the author, and if all were thoroughly dry, no differ- 
ence could be noted in the carrying qualities of the dif- 
ferent kinds of whitewood, and the preference has been 
for well seasoned basswood cases. It may be that bass- 
wood is more likely to sour and affect the eggs than 
poplar or cottonwood, but it is always advisable to get 
stock for egg cases in the fall and have them nailed up during 
the winter, allowing two or three months for the cases to season 
and dry out before the opening of the egg storing term. Some 
have dry kilns for cases, but a naturally seasoned case is to be 
preferred, as then it has a chance to deodorize as well as dry out. 
In some localities other woods are used for egg cases. Ash, 
maple, hemlock and spruce have been used for storage cases, 
generally because they are cheaper than whitewood in that locality. 
Any strong scented wood like pine will not do because of the 
flavor imparted to the eggs. 

The pasteboard frames and the horizontal dividing or sepa- 
rating pasteboard pieces which form for each egg an individual 
cell in the case are usually spoken of as fillers. For years only 
one grade of these was made — those of ordinary strawboard. 
When moistened by the evaporation from the eggs this material 
has a peculiar rank odor, which was taken up to some extent by 
the eggs if they were allowed to remain in the fillers for several 
months. Much of the flavor resulting from a growth of fungus 
has been laid to the fillers, and much of the flavor resulting from 
fillers has been laid to a growth of fungus or must, but there is 
no question about strawboard fillers not being a perfect material 
for cold storage use. Many kinds of fillers have been tried, and 
many ideas suggested for the improvement of cold storage eggs. 
A whitewood pulp filler made its appearance some years ago, but 


did not come into general use. After being in storage a few 
months, it absorbed moisture to such an extent as to become 
very soft, and they were objectionable on this account. A good 
manila odorless is now on the market which is giving good satis- 
faction where tried. Ordinary strawboard fillers have been 
coated with various preparations, shellac, paraffine, whitewash, 
etc. Any substance in the nature of waterproofing might better 
be left off for the reason, as we have seen, that eggs must evap- 
orate, and a waterproof filler would hold the moisture and not 
allow it to escape into the air of the room. It is essential to the 
well being of an egg that it should evaporate, as proven by the 
experiments in hermetically sealing, before described. Many have 
gone to the expense of transferring the eggs into dry fillers in 
the middle of the season. One season of this was enough for the 
author. A better way is to decrease the humidity of the room 
as the fillers become more and more loaded with moisture. The 
humidity may be decreased by the use of absorbents or by ventila- 
tion, as already discussed in their proper places. Fillers made of 
thin wood have been used in years gone by with fair success, 
but their manufacture has now been entirely discontinued. They 
were made of maple, shaved very thin, and were a prime filler so 
far as odor was concerned, but in cold storage the frames warp 
badly, and the time and eggs wasted in getting the eggs out 
of the fillers was a serious item against their use. As a shipping 
filler they were also a failure because of the excessive breakage. 
Some years ago an eastern company began the manufacture of 
what is known as the odorless fillers. These fillers are light 
brown or buff in color, and from the best information the author 
can obtain, are composed largely of scrap paper stock, with some 
long fibre like manila added for strength. In the manufacture 
the stock is treated to a thorough washing and deodorizing proc- 
ess, and the result is a filler with very little odor. Eggs put up 
in these so-called odorless fillers and subjected to the same con- 
ditions as a similar grade of eggs packed in common straw- 
board fillers, have come out of cold storage in better condition 
in a good many cases. A number of imitations of the original 
odorless filler are now on the market, some of them almost if 
not quite the equal of the original. Another filler which has 
^iven good results is the fibre filler, wdiich is made from a material 


similar to the now well known fibre ware. They have very Httle 
odor, and remain hard and firm while in cold storage. A new 
odorless filler made from pure spruce pulp has been put on the 
market. This is a beautiful appearing filler, and unless appear- 
ances and the ordinary tests are deceptive will make its mark 
after a trial of a year in cold storage to prove what it can do. 
A ventilated filler made by a well known creamery supply house, 
has been suggested as an ideal filler for cold storage, but they 
are so poor mechanically that they are not to be thought of. 
The material cut away to form the air circulation space weakens 
the structure of the filler to such an extent as to make it danger- 
ous as a shipping filler. Whatever filler is used, it should fit the 
cases, not crowding in, nor still so loose as to shake. If this point 
is looked after much breakage and consequent poor results from 
storage in the cold room may be avoided. 

Many styles of ventilated egg cases have been placed on 
the market in years past, but very few or none survive the test of 
time. A ventilated case, made by having the sides cut an inch 
narrower than the ends, has come into use, especially in one 
large eastern city. Making the sides narrower forms a space of 
half an inch on both sides of case at top and bottom, for the 
ready access of air to the interior of the case. This case is of 
very simple construction, and efficient in allowing a free circula- 
tion of air into the case. Others, however, prefer a case with 
sides in two pieces, claiming that the cracks will allow enough 
air circulation. Still others prefer the shaved or veneered 
cases with solid sides and bottom, claiming that this kind of a 
case will prevent excessive evaporation from the eggs. As pointed 
out elsewhere, humidity and circulation have much to do with the 
evaporation from eggs ; in fact, are more of a ruling factor than 
the package, although the package necessarily has much to do 
with it. A tight package will allow of less evaporation than an 
open one. In a very dry room with a vigorous circulation a mod- 
erately tight package is the thing, but in a comparatively moist 
room with poor circulation the more open the package the better. 

An appreciation of the poor circulation and damp air of the 
overhead ice systems has caused many of their operators to resort 
to the use of open trays or racks for the storage of eggs. \'ery 
palatable eggs have been turned out in this way, but the use of 


trays in any ammonia or brine cooled room would lead to very 
excessive shrinkage of the eggs and consequent heavy loss in 
candling. On a commercial scale, too, the storing of eggs in 
trays is hardly practicable, as it increases the risk of breakage 
immensely, and the eggs must be transferred from the cases when 
received at the storage house, and back into cases again when 
shipped, involving much labor, and perhaps loss of valuable time 
at some stages of the market. In any but a very moist room, 
eggs stored in open trays, in bulk, will lose much from evapora- 
tion, and the loss will be proportionately higher than on an equal 
grade of eggs stored in ordinary cases and fillers. The ad- 
vantage of trays, if any, for some houses, is that contamination 
from fillers is avoided, and about 40 per cent more eggs can be 
stored in a given space. The eggs are, however, more liable to 
must as a result of moisture condensing on their surface with 
change of temperature, or on the introduction of warm goods 
into the storage room. 

The material used for forming a cushion in the case on top 
and bottom of the fillers to protect the eggs from contact with the 
case, and so that they will carry in shipping, is generally either 
excelsior, which is finely shaved wood, usually basswood, or the 
chips made in the manufacture of corks, known as cork shavings. 
The big cold storages have in the past recommended cork in 
preference to the best excelsior. Here again comes a question 
of dryness. If the excelsior has been in stock for a year and 
stored in a dry place it is to be preferred to cork shavings, 
otherwise cork is the best, because we know cork is always dry. 
Cork makes a very poor cushion as compared to excelsior ; it is 
liable to shift in the case, leaving one side without protection. 
As a matter of cost, too, cork is much more expensive than ex- 
celsior. A company known to the author manufacture a beautiful 
grade of basswood excelsior, which is always fairly dry when 
received, and makes as fine a cushion for protecting the 
eggs as can be desired. If people w-ant cork in their cases 
they can have it by paying the price, but dry, seasoned, fine 
basswood excelsior is better, for reasons stated. Tlie best 
houses are now recommending dry excelsior in place of cork 
on account of the excessive breakage when a cushion of cork 
is used. 


Eggs have been packed in oats for years, but the practice 
has gradually fallen off, as eggs stored in cases from the best 
cold storage houses have been improved in quality frcmi year 
to year. Oats, if dr\% will absorb moisture from the eggs quite 
rapidly, and are objectionable on this account. If the oats are 
not dry the germs of mold are developed rapidly, and as the 
moisture is given off by the eggs the mold will grow, causing the 
eggs to become "musty." Therefore the main difficulty in using 
oats as packing for eggs in cold storage is to have them at the 
correct degree of dryness. It is almost impossible to have them 
in the same condition at all times. Oats have also been used in 
cases inside the fillers; that is, the layers of eggs are first put 
into the filler ; then the oats are sifted into the spaces around the 
eggs flush with the top of the filler. This is repeated through 
tlie whole case ; all the space in the case not occupied by the eggs 
being filled with oats, excepting the small space taken by the 
fillers themselves, the object being, of course, to prevent the 
"filler taste." 

At intervals we read of some method of preserving eggs, 
which is said to be sure to supersede ordinary cold storage for the 
good keeping of eggs. A scheme was tried on a large scale 
somewhere across the water, in which the eggs were suspended 
in racks in a cold room — the racks being turned at regular in- 
tervals by automatic machinery to keep the eggs from spoiling; 
that is, to keep the yolk from attaching to the shell. A low 
temperature will prevent this, as pointed out in this chapter 
under the head of " Temperature," and why a man should waste 
good energy inventing such a machine is passing all comprehen- 
sion. The quantity of various chemical preparations manufac- 
tured and sold for egg pickling or preserving is even now quite 
large, but the high class stock now turned out by the best 
equipped cold storage houses has made any other method of pre- 
serving eggs at the present day almost entirely obsolete. 


There is a long string of "don'ts" in regard to packing, 
handling and storing eggs which might be put down, but the 
author will be content with a few of the simpler and most useful 
ones. To start with, don't store very dirty, stained, cracked, 


small or bad appearing eggs of any description. Have your 
grade as uniform as possible. The culled eggs will usually 
bring within two cents of the market price, and it pays better 
to let them go at a loss rather than try to store them. Don't 
use fillers and cases the second time; they are more likely to 
cause musty eggs than new ones. Don't ship eggs in cold cars, 
or set eggs which are intended for storage in ice boxes. In 
shipping eggs from the producing section to the storage house 
in refrigerator cars, no ice should be put in the bunkers, be- 
cause if the eggs are cooled down and arrive at their destination 
during warm or humid weather they will collect moisture or 
"sweat," and an incipient growth of mold will result. Don't 
use heavy strawboard fillers for storing eggs. If "the best 
way to improve on a good thing is to have more of it," then 
the best way to improve on a poor thing is to have less of it; 
and if strawboard fillers are objectionable, then the thinner they 
are the better, because less of the material is present to flavor the 
eggs. Further, the thin board fillers are more porous, and allow 
of a freer circulation of air around the eggs. The grade known 
as "medium" fillers are best for cold storage purposes. As already 
stated, odorless fillers are better than any strawboard fillers. Don't 
use freshly cut excelsior. It should be stored in a dry place at 
least six months. Use no other kind but basswood or whitewood. 
Don't store your cases, fillers or excelsior in a basement or any 
damp place. Don't run warm goods into a room containing 
goods already cboled when it can be avoided. For this reason 
very large rooms are not to be desired. A small room may 
be quickly filled with goods and closed until goods begin tj go 
out in the fall. If a large room is used it may require several 
weeks to fill completely, during which time the fluctuation of 
temperature is at times excessive, causing condensation on the 
goods, which will propagate must quickly. 

To illustrate: We will suppose the egg room partly filled 
with goods cooled to a temperature of 30° F. Several cars of 
eggs at a temperature of, say, 70° F. are run into the same 
room. The new arrivals, in cooling to the low temperature, 
give off large quantities of vapor from cases, fillers and the 
eggs themselves, the vapor condensing, of course, on any ob- 
ject in the room which is below the dew point of the air from 



which the warm gcK)ds came. This may seem like a finely spun 
theory, but the author has had some experience which amply 
justifies this explanation. That the moist vapor given off by 
the warm goods does not show in the form of beads of water, 
or fog, or steam, is no proof that it does not exist. If the ex- 
tremes of temperature are as great as 25° F. condensation will 
occur on nine days in ten during the Qgg storing season. The 
goods already in storage are raised in temperature materially 


by placing in warm goods, which is harmful to some degree. 
The logical deduction from above seems to indicate that warm 
goods should not be placed in a room with goods which have 
been reduced to the carrying temperature. A separate room 
should be provided for this purpose near the receiving room 
in which the goods coining in warm may be cooled to very near 
the temperature of permanent storage room. This is a refine- 
ment which small houses cannot afford, and which most of the 
larger ones do not have. 



If you wish to progress compare your results with those 
of others. Don't say: "My eggs are as good as fresh;" test 
carefully from time to time through the season and compare 
quality with those from other houses. 

It should be positively understQod that merely theoretical 
knowledge on this subject is of only limited assistance; and 
those who undertake new work are advised to put a man in 
charge who has had experience with the product which it is 

5Uclf for plUrJtC n 


Ifc^-k^U BOOTH 



proposed to handle in storage, as well as acquaintance with 
the mechanical details of the plant. 


The construction of rooms to be used for the testing or 
candling of eggs has not reached a stage where it may be 
stated that there is any design which might be called standard 
or that is generally approved by the trade. Nearly every pro- 
prietor has his individual ideas on this subject, and, therefore, 
nearly every different plant is fitted up in a different way. The 
booth system, which consists of individual stalls or separate 
small rooms for each person, is coming into general favor. The 
advantage of this system is that each person works by him- 
self, and, therefore, better work is possible, and each operator 
must stand on his own individual merits. In other words, the 



system allows of a closer inspection and a closer systematizing 
of the important operation of candling eggs. 

The number of booths necessary depends upon the volume 
of business to be handled and any number of booths may be 
arranged in a large room, ,which may be called the "Candling 
Room." (See Fig. 6.) Candling is simply a misnomer in this 
connection and originated from the fact that a candle was or- 

5k«lf f< 







iginally used for testing eggs. Very few candles are now in 
use for this purpose and the electric light is in general favor. 

The construction of the booth is subject to some modifica- 
tions ; the one shown in accompanying view, plan, section and 
elevation, also detail of candling box or candler (see Figs, i, 
2, 3, 4, and 5), has been proved by practical service to be eco- 
nomical of space and, withal, convenient. As shown, sufficient 



shelf room is provided for fillers above a plank table on which 
rest cases which contain the eggs to be tested and for the dif- 
ferent grades into which the eggs are classed. With the size 
booth shown, sufficient room is provided for five cases on the 
table. The booth may be constructed of a single thickness of 
boarding on three sides and top, the fourth side being closed by a 
curtain of heavy, d^rk colored denim, or any suitable material. 
This curtain should be hung on a wire or rod with rings so as 
to slide easily, and it may or may not be divided in the center. 



• HeU< ilfJifiMn. 


In Fig. I, which is reproduced from a photograph, is shown 
the booth system in service. The white candling boxes show 
plainly in the center of the booths. Cork shavings used as a 
cushion at top and bottom of egg cases are shown in the box 
between booths. The barrels are intended to receive the litter 
of various kinds, such as old newspapers, which accompany 
country packed eggs. The pail for rots is shown above the 

The candling box or candler which contains the electric 
light or lamp may be constructed of ordinary egg case material 



one-quarter of an inch thick. One-half-inch quarter round is 
nailed into three corners of this box, inside, to strengthen it. 
The fourth corner is pierced with two holes placed close together, 
as shown in the detail. The holes should be one and one-quarter 
inches in diameter. The bottom of the candler is left open so 
that light from the electric lamp may be thrown into the cases 
on the table below. The top of the candler may be partly 
closed by a piece of cardboard, or otherwise, in case too much 
light is reflected to the ceiling so as to make the candling room 


too light for close candling. The circulation of air, however, 
through the candling box should not be entirely shut oflf, for the 
reason that it will cause rapid destruction of the electric lamps 
by overheating. 

In the place of the candler shown in the drawings, many 
prefer to use a round tin candler with a single hole, which will 
accommodate either one or two eggs as desired. There is also 
now on the market a very simple and perfect little rig which 
may be had at a reasonable price for use with either the electric 
light or kerosene lamp. 


The details of candler or tester are subject to many modi- 
fications to suit individual ideas. The question of candling two 
eggs at once or singly has been much discussed among profes- 
sional egg candlers. Many prefer the candler with two holes, 
and still others insist that one hole is sufficient. The author 
has personally used the booth and candler described and be- 
lieves it to be equal to anything which has come to his knowledge. 
All dimensions are given on the diagrams so that the construc- 
tion of the booth system as above described will be simple for 
those who desire to -test the practicability of the scheme as ap- 
plied to their local requirements. 

The room in which the booths are arranged, or what may 
be called the candling room proper (see Fig. 6), should be of 
sufficient size to accommodate the handling of goods in and 
out of the room and allow space for empty cases, fillers, etc., 
and it should also be large enough to provide storage space for 
one or two days' packing. The room should be insulated in 
any fairly substantial manner, and means for maintaining same 
at about 60° F. in warm weather should be provided. In other 
words, we should provide a cold storage room for candling 
eggs. Eggs coming in from the country during warm weather 
may be placed at once in this room and should be reduced to a 
temperature of about 60° F. before being candled. 

It is fully understood among practical tgg shippers that 
when eggs come in from the country in hot weather they often 
appear to be in very much w^orse condition than they really are. 
After being cooled to about 60° F. the eggs may be candled and 
judged for their actual quality. A refrigerated candling room 
is also a great benefit in stopping further immediate deteriora- 
tion when the eggs come in heated. The more progressive 
modern egg houses which are being erected at the present time, 
where cold storage is an adjunct, have refrigerated candling 
room facilities. The value of these arrangements will be at 
once appreciated by those who have had experience in candling 
eggs during the heated term. 

The candling room may be refrigerated in any suitable 
way, but a fan system of air circulation is generally preferred 
about on the lines shown in plan of candling room. In this way 
the cold air from coils is distributed along the floor on the 




opposite side of the room from the operators and the warm air 
is taken out over their heads, above the booths. It is advisable 
to provide openings in the top of the booth for a circulation of 
air; these openings to have hinged doors so as to regulate the 

The cooling pipes may be placed in a box or bunker near 
ceiling of the room and a drip pan provided underneath. This 
will avoid all dripping or spattering on the goods or cases, and, 
by distributing and drawing off the air as suggested, uniform 
temperatures are obtained and strong drafts are prevented. If 
the room is reasonably high, fairly good results may be obtained 
by placing the cooling pipes on the side walls near the ceiling 
and providing drip gutters beneath, or the room may be cooled 
by natural ice by proper arrangement of openings from the 
source of ice supply. If the refrigerated candling room is once 
put in service for use during hot weather, its advantages will 
be so apparent that the operator will wonder how he was ever 
able to get along without it. 




In the early days of butter refrigeration it was thought 
that temperatures of from 35*^ to 40° F. were sufficiently low. 
These temperatures kept the butter in a reasonably solid state, 
and for periods of two or three months gave good results in 
preserving the flavor and preventing deterioration. The ten- 
dency has been steadily toward lower temperatures until now 
zero and below is thought by many to be best for butter storage. 
This is by no means a general impression, and the majority of 
produce men still believe that any temperature below 20° F. is 
sufficiently low for ordinary commercial results. It may be 
stated that the average of opinions on the subject at this time 
favors 12*^ to 15° F., and as there are no results of accurate 
tests available at this time to prove any particular temperature 
as best for varying conditions and purposes, the present status 
of the matter is presented for the consideration of the reader. 
The author has maintained for some time that any temperature 
below 20° F. was low enough for periods of two to five months, 
which covers the average time for which three-fourths of the 
butter is cold stored. If the butter is stored in suitable packages, 
and is well made to begin with, no good may be accomplished 
by storing at lower temperatures. On the other hand if the butter 
is in packages not suitable, of inferior packing and gradC; and 
it is desired to store for long periods, or it becomes necessary 
to carry from one year to another, temperatures of from 10° 
above zero to below zero Fahrenheit may produce improved 
results. It is certain that 20° F. and below will retain the desir- 
able butter flavors better than from 35° to 40° F., so it appears 
reasonable that 10° F. above zero and still lower will retain 
flavors better than 20° F. or thereabouts. For a number of 


years the author has constantly recommended a temperature of 
from 12® to 15° F. for average butter storage, and sees no reason 
at this time to change. If tests which are at al! conclusive prove 
differently he will not be backward about recommending lower 


We hear nowadays about freezing butter for holding in 
storage. This commonly refers to any temperature below the 
freezing point of water (32*^ F.). Some houses have recom- 
mended and practiced ^'freezing" the butter at zero or there- 
abouts for a few days, and then storing permanently in a tem- 
perature of from 10° to 20° F. above zero. Butter does not 
freeze in the ordinarily accepted sense of the term. It is of an 
oily nature, and simply gets harder and harder as the tempera- 
lure is reduced. The freezing point of butter, if it may be so 
called, is from 92° F. to 96° F. as determined by test. (See 
"Specific Heat of Butter" further on.) The freezing point of a 
substance, as ordinarily understood, means the temperature at 
which it changes from a liquid to a solid, and butter therefore 
freezes at many degrees above the freezing point of water. The 
talk about rupture of fat globules in butter by freezing, there- 
fore, is not well applied. Butter does not freeze at any cold 
storage temperature, but simply becomes harder and denser as 
the temperature is reduced. It will, however, probably be ulti- 
mately shown by Government tests that storing butter at an 
extremely low temperature will cause a "shortness" or rup- 
ture of the grain, but this is advanced by the author on his own 


The successful holding of butter in cold storage has in the 
past hinged as largely on the protecting of the product from the 
air as in maintaining a low temperature in the cold room. Pos- 
sibly with extreme low temperatures of zero or thereabouts, pro- 
tection from the air will be of less consequence, but this point 
cannot at present be overlooked if best results are desired. 
Butter being composed largely of an oil or fat, is susceptible of 
becoming rancid or " air-struck " when exposed to the air for a 



considerable time; the higher the temperature the quicker the 
butter becomes rancid. It is reasonable to suppose, therefore, 
that the lower the temperature the longer butter may be held in 
contact with the air without becoming rancid. In other words 
as the temperature of a butter storage room is held lower, the 
less the necessity of care in protecting the butter from the air of 
storage room. It is in any case desirable that the package should 
be as air-tight as possible. It cannot be known at time of 
storing how long the butter will be held, and the nearer air-tight 
a package is, the longer will it keep the butter in good flavor 
and condition. Butter packed under direction of the United 
States Government for export and use in warm climates is put 
up in hermetically sealed cans, and some of our "boys in blue" 
bear witness to the palatability of same, even when carried under 
insufficient and inferior methods of refrigeration. Another means 
of canning is the method formerly in use for packing butter for 
shipment to California. The butter was made up in rolls and 
packed in tight casks which were afterwards headed up and all 
spaces between rolls and at sides and ends of casks were filled 
with brine or "pickle" as it is called. As the refrigerating means 
were formerly inadequate, this method was necessary in order 
that the butter might be carried through to destination in pal- 
atable condition. Firkins (kegs holding about loo lbs. of but- 
ter) were much in use at one time, especially for shipment to 
foreign countries. These wooden packages were thoroughly 
soaked with brine, packed solid and nearly full. The head was 
put in and when the butter was cooled, the remaining space was 
filled with pickle composed of salt, saltpetre, and sugar. At- 
tempts have also been made to cover the butter in ordinary tubs 
with brine pickle after the tubs were placed in storage, in order 
to protect the butter from the air, but the muss and slop resulting 
made this scheme impracticable. These methods of packing 
butter are mentioned as representative of the former practices in 
use to prevent the butter becoming air-struck and rancid. At 
this time very little butter is stored under any of these methods, 
owing to the expense of packing and impracticability of the 
packages for the retailer. Butter stored immersed in pickle also 
has a soaked appearance, where it comes in contact with the 
pickle, which is objectionable. 



It was at one time thought that flavor and aroma of butter 
were due to the food upon which cattle were fed. During the 
"full grass" months of May, June, and July, this was especially 
noticeable, and at this time cows give milk which makes a fine 
quality of butter. The bacteriologist has changed our ideas on 
this matter, and by the use of a "culture," nearly as fine an 
aroma and flavor may be produced in midwinter as on full grass. 
By Pasteurization and ripening the cream by the use of a culture 
of suitable bacteria, fine flavored butter may be made at all sea- 
sons of the year. One of the chief desires in cold storing butter 
is to retain the flavors and aroma which are produced by the 
ripening or souring bacteria of milk and cream. Loss of these 
is prima facie evidence that butter is no longer fresh. Low 
temperature and protection from the air will accomplish the 
desired results. 


Butter intended for cold storage purposes should have the 
buttermilk thoroughly removed by washing and working mod- 
erately in water. The working should not be carried too far so as 
to spoil the grain of the butter, but as much of the buttermilk as 
practicable should be worked out and a moderate amount of pure 
water and salt incorporated in its place. The butter should be 
well salted so that the water content shall be in the form of strong 
brine. Butter containing a large portion of moisture keeps best 
in cold storage. Butter made by the old deep setting process or 
by raising the cream by setting in cold water, keeps much better 
than the best separator butter. No doubt some will be somewhat 
surprised to learn this. The reason is that more of the casein 
is left in the butter by the centrifugal separator which causes a 
fermentation which deteriorates the butter more rapidly. The 
author has seen two lots of butter placed in cold storage at the 
same time and stored in the same room — one lot was fancy 
separator creamery butter worth about i8c per lb.; the other 
lot was a second grade gathered-cream creamery, worth 14c 
per lb. When removed from storage four or five months later 
the 14c butter sold the best on the open market. The gathered- 
cream butter, as most of my readers are aware, is made from 


cream skimmed by the farmer and collected and churned at a 
creamery. The resulting product is always inferior in flavor 
when first made. The case above is mentioned to show the com- 
parative keeping quality of centrifugal separator and gravity 
raised cream butter when placed in cold storage. Possibly at the 
low temperatures now advocated by some, this difference will 


** Process" or renovated butter, which is made from a mis- 
cellaneous lot of dairy butter melted, purified, regranulated and 
flavored by the use of a bacteria culture, has comparatively poor 
keeping qualities in cold storage and therefore very little is 
stored. The most common way is for the process operator to 
store the original package or by repacking into barrels. If 
barrels are used they should be soaked v.^ell with brine and then 
lined with parchment paper before packing in the butter. Don't 
store rancid butter for processing — select only that which is fresh 
and reasonably sweet. Butter which is slightly sour from pres- 
ence of buttermilk is not as good for cold storage, but in process- 
ing this largely disappears, and butter which is sour from this 
cause may be stored to advantage if fresh. In fact, it is difficult 
to get the medium grade dairy butter which is largely used for 
processing, during the months of June and July, which does not 
have more or less this sour character. The chief point of im- 
portance to guard against in selecting butter to be cold stored 
for future processing is rancidity. Butter which has once become 
even slightly rancid will deteriorate more rapidly in cold storage 
and is unfit for making anything but low grades of process 
butter. Store in the original package if possible, providing it is 
in good condition, as repacking breaks the grain and injures the 
keeping quality. If it is necessary to repack, pack solidly with- 
out leaving air holes. 


For a limited local trade a good grade of dairy butter in 
small jars is very desirable. Select good flavored, even colored 
butter for storage, and turn everything else into ''packing stock" 
or low grades. Remove all miscellaneous cloth and paper cover- 


ings, replacing by cloth or parchment paper circles or caps and 
spread on evenly a fine grade of dairy salt to a thickness of one- 
eighth of an inch, or sufficient to cover the surface of the butter 
thoroughly. Over this tie a cover of light colored manilla wrap- 
ping paper, and you have a package which is practically air 
tight. It is also in good shape for sale when removed from 
storage. The jars may be piled one upon another to a height 
of three or four feet. Racks are best for piling jar butter with 
shelves at intervals of three or four feet. In piling in an ordinary 
room without racks, there is great danger of a collapse of piles 
of jars and the result may be imagined. Jars arc undesirable 
for shipping, hard to handle, and liable to be broken, but they 
make a fine package for cold storage, and are desirable for retail- 
ing, especially during the fall of the year before roll butter makes 
its appearance. For storage in a small way, for local consump- 
tion use jars. 


Tubs of various sizes larger at the top are the standard 
butter packages, and by far the greater portion of the butter 
made in the United States is handled in tubs containing about 
sixty pounds. The best material for tubs is white ash, but some 
markets, notably Boston, prefer tubs made from white spruce. 
The covers of tubs should be of the same material as the staves 
and bottom, or of some sweet hard wood. The soft woods, par- 
ticularly pine, may impart a foreign flavor to the butter. The 
following directions for soaking tubs and preparing them for 
packing are given by P. M. Paulson:* 

In packing butter it is first necessary to properly prepare the pack- 
age; this I do by soaking the tub and then placing in a tank of brine 
so that the tubs are held completely in the brine for about 12 to 14 hours. 
The liners 1 also place in brine for about the same length of time. When 
butter is worked sufficiently and ready for packing, I line the tubs. If 
I am alone to pack, I line five or six tubs at a time; if my helper has time 
to help me, we line enough tubs to hold what butter we have in a work- 
ing. The liners we place in smoothly in the tubs in a way so that the top 
edge of the liner can be turned down over the edge of the tub about 5^ 
inch. Next I put the bottom circle in position. If I am packing alone, 
I take five oi* six pounds of butter (not more) and put in each tub that I 
have lined; I then press it firmly together with the packer, seeing that 
there are no boles left in the butter and also that it is pressed firmly 
against the edge of the tub. I repeat this operation until tub is filled and 

•In Nexv York Produce Review. 


enough more so that there is from one to two pounds on top. When this 
has been pressed firmly down, I take a string, wet it, and cut the butter 
off level with the tub; next I take the paper lining and turn it back oyer 
the edge of the tub and on to the butter, neatly and with care, being 
careful not to tear the paper, and smooth it down. Then I place the 
cloth circle on the tub ; this should be large enough to reach to the out- 
side edge of the tub. Then I take a little water with my hand and moisten 
the cloth, next sprinkle a little salt on, and rub it lightly with my hand, 
so that it is even all over. In placing^ the cover on, care must be taken 
to get it on properly; if it don't go on easily I place my knee on the 
cover and tap the edge lightly with a hammer until I get the cover on; 
it is better to hammer on the edge of the cover than to hit the staves on 
the tub, as it keeps the butter in better shape. In placing the tins, I place 
the first one on over the end of the cover rim ; this will prevent the rim 
from tearing off if it should by accident get caught; the second tin I place 
directly across from the first one, the third and fourth at equal distance 
between first and second. I always try to place the tins so that they will 
reach down into the top hoop on the tub; last I drive a ^d. nail in the 
lower end of tin; the end on the cover I have always found does very 
well with on^ nail. I always use a tin that has one nail in each end; 
they are the most convenient to use. Wire tub fasteners should not be 
used, the trade does not like them. Before I place butter in refrigerator 
I always see that the tubs are perJFectly clean. 

The liners mentioned by Mr. Paulson are of parchment paper 
and come ready cut to proper size for tub used. A pint of brine 
in the bottom of the tub when starting to pack, is desirable, as it 
fills all cavities and the pores of the wood. In packing keep the 
butter pressed down in the center first and then at the sides so as 
not to leave openings in the butter which may later become air 
spaces and cause the blitter to sooner become *' air-struck." 


Oleomargarine and butterine are of a similar nature and 
resemble butter, but are much more easily preservable by re- 
frigeration, and may be kept for long periods in fine condition. 
The reason is that they contain very little casein or other sub- 
stance liable to fermentation and decay, being composed almost 
wholly of fats and oils which do not spoil quickly, even at ordi- 
nary temperatures. A temperature somewhat higher than that 
recommended for butter is generally used for butterine and oleo- 
margarine. Temperatures of from 20° to 30*^ F., are in com- 
mon use for the storage of these products. 


"Ladle" butter is butter reworked, resalted and repacked, 
so as to put it in marketable condition and give it a uniform 


grade. Much of this is butter of good quality, but lacking in 
uniformity of color, salt, and package. The ladler takes the mis- 
cellaneous "farmers," "dairy," "store" or "packing stock" butter, 
and by rehandling turns out a butter which is improved com- 
mercially to an extent which has in the past made the business 
profitable. The ladler makes his profit in intelligent grading 
and in the increase of weight by resalting, washing, and rework- 
ing. "Ladling" has now been largely . superseded by "process- 
ing." Very little ladle butter is placed in cold storage at the 
present time. Those who have had experience, know that 
"ladles" do not keep well in cold storage. The reworking incor- 
porates thoroughly throughout the mass any rancidity or bad 
flavor present in any part of the butter, and the result is that 
after standing a comparatively short time "ladles" are off flavored 
and take on a "ladley" taste and odor, even when carried in low 
temperatures. As in processing, butter intended for ladling is 
cold stored as original butter and rehandled as wanted by the 
trade. Directions given for the handling of original butter apply 
equally when used for processing or ladling. 


Creamery butter is so well known as not to need much de- 
scription. At the present time nearly all creamery butter is 
made from cream which is separated from the milk by a centrifu- 
gal machine known to the trade as a separator. Separator butter 
has poorer keeping qualities than butter made from cream raised 
by setting the milk in cold water or what is called the gravity 
process, for reasons already stated, but for the ordinary com- 
mercial storage term of three to five months, keeps well enough 
for practical purposes when held at temperatures below 15° to 
20° F. The sixty-pound tub is the package generally used, par- 
ticularly by the retailer, but much butter after having been 
stored in large tubs is tempered to soften slightly and then 
repacked into smaller packages ; the one pound print, wrapped in 
paraffine or parchment paper being a favorite. Butter which is 
to be "printed" before sale should be stored in as large, air- 
tight and well soaked or impervious packages as possible. Some 
dealers use firkins or butter carriers holding 100 to 200 pounds. 
Do not try to store butter in prints for any length of time as 


the grain is somewhat broken in printing and its keeping qualities 
therefore impaired. For the same reason do not store in small 
packages which are not impervious to air and moisture. The 
directions for packing previously given apply especially to cream- 
ery butter. In some cases a covering of paste salt (salt which 
is ground fine) is used. This is mixed with water and is put 
on as a paste, which hardens on drying, forming an air tight 
crust over the top of the butter. The butter cannot well be 
examined without mussing or destroying this paste salt covering, 
and it is not used to any extent except for cold storage purposes. 


Mold in butter packages has given much trouble, both in 
cold storage and in the regular cooling rooms when held for 
temporary storage. This may be caused by improper soaking 
of the tubs or a badly constructed refrigerator or cooling room 
at the creamery, or the empty tubs may be stored in a damp 
place such as a cellar or basement at the creamery. A growth 
of mold once started is quite likely to continue to grow and m.ay 
in a short time affect and flavor the butter. A growth of mold 
may be prevented by storing the empty packages in a dry place ; 
providing a good refrigerator with suitable air circulation at 
the creamery; and by care and attention in packing the butter, 
as already outlined. Instead of using water for soaking the 
tubs, use brine. Water promotes mold — ^brine destroys it. Salt 
is cheap. Use it in connection with your butter packages, and 
mold will not trouble you. Use parchment paper liners and use 
brine for moistening at time of packing. See chapter on "Cream- 
ery and Dairy Refrigeration" for information regarding suitable 
facilities for cooling rooms, etc., in connection with creameries. 


The following regarding the specific heat of butter* by 
G. H. King, Agricultural Physicist, University of Wisconsin, is 
reproduced here for the valuable scientific information it 
contains : 

It would be a very difTicnlt, if not an impossible, task to determine 
the true specific heat of the butter fat of commerce, making corrections 

♦From Ice and Refrin^eration, June, 1901. page 278. 


for the elements of latent heat, for the reason that butter is so complex 
a product, and the butter fat itself varies so much in composition with the 
season and with the stajre of the lactation period, and even with the 
individuality of the animal producing the butter. 

I have made an approximate determination of the specific heat of but- 
ter fat between ioo° C. and o° C, and find it to be .5494- 

This result was obtained by taking ordinary butter, melting it and 
boiling until all water was driven oflF, and skimming to remove solids not 
fat, and then filtering hot. 

There was then placed into a pocket in a block of ice 200 grams> of 
the clear butter fat at a temperature of 100" C, and brought quickly 
to 0° C, when the butter fat and ice melted were weighed. Calculating 
the specific heat from the amount of ice melted, the result found was 


Butter fat, leaving the other ingredients out of consideration, is largely 
a solution of tripalmitin and tristearin in triolein, or, in commercial 
language, butter fat is a solution of palmitin and stearin in olein. But in 
addition to these three fats there are also found varying amounts of five 
others, viz., butyrin myristin. caproin, caprylin and caprin. 

The pure triolein, or olein of vegetable fats and oils, becomes solid 
only at a temperature as low as 21° F. The tripalmitin, or palmitin of 
vegetable and animal fats, occurs in three isomeric or allotropic forms, 
with melting points as high as 115°, 142° and 144° F., respectively, while 
the tristearin, or and vegetable stearin, also occurs in three forms, 
which remain solid, when pure, until a temperature of 124°, 148° and 157° 
F., respectively, is reached. 

The temperature at which butter becomes' solid, or semi-solid, varies 
with the relative amounts of the three chief fats which happen to be 
present in the sample. It is stated that ordinarily butter becomes fluid 
or melts at between 92° and 96° F., which should be understood that be- 
low these temperatures the olein is no longer able to hold all of the 
palmitin and stearin in solution. Pure lard melts at 78° to 87° F., and its 
composition is given as 62 per cent olein and 38 per cent of palmatin and 
stearin. Butter fat, in the spring, from fresh cows on green grass has a 
composition near 50 per cent of olein, 30 per cent of stearin and 20 per 
cent of palmitin ; but later in the period of lactation, and in the fall when 
the feeds are drier, its composition may change to 30 per cent olein, 50 
per cent stearin and 20 per cent palmitin. 

It seems likely from these observations that the amount of heat neces- 
sary to be applied to butter, in raising it from freezing to its melting 
point, and to be withdrawn from it in cooling it from its melting point 
down to freezing, will not be very far from the amount which would be 
required to make a corresponding change in temperature of water, pound 
for pound. 


Humidity, air circulation and ventilation have been p^iven 
comparatively little attention as applied to the storage of butter. 
At the low temperatures at which butter is generally stored the 
air contains so little moisture as to Be amply dry to prevent mold, 
and nothing further is thought of it. In fact, most butter storage 
rooms are dryer than necessary, and it is difficult to prevent the 
butter drying out from this cause. It is only necessary to have 


a butter room dry enough to prevent mold on packages, as the 
goods are supposed to be sealed from air contact. What this 
humidity should be there are no records to show, but moisture 
does not trouble the general run of storage rooms for butter. A 
circulation of air in butter storage rooms is of no great conse- 
quence, as sufficient air circulation for purification of the air is 
usually present. Most butter storage rooms are equipped with 
direct piping, but some are provided with air circulation by 
means of fans, when a quicker cooling is possible. Ventilation 
of butter storage rooms is advisable at regular intervals, using the 
apparatus described in the chapter on '* Ventilation." Gases from 
the oxidizing of butter fat and odors from the wooden packages 
accumulate in the storage room unless disposed of by ventilation. 




The cold storage of cheese on an extensive scale is one of 
the recent additions to the cold storage business. Formerly it 
was considered sufficient to store cheese in an ordinary cellar 
or basement room, but about twenty-five to thirty years ago 
cheese were first placed in cold storage, both with the old over- 
head ice method of cooling and the first ammonia refrigerated 
houses. The author remembers distinctly when as a boy he vis- 
ited the old St. Johns Park Depot in New York, which was then 
cooled with one of the first ammonia systems to be put in com- 
mercial cold storage service and was used quite largely for 
cheese storing. The success of the early experiments in keeping 
cheese in cold storage was such as to extend the practice and 
at the present time practically all cheese which are to be held for 
consumption at some future time are placed in cold storage for 
preservation. In fact the advantages of cold storage have been 
so thoroughly appreciated that it has led the various experiment 
stations of the United States Department of Agriculture to con- 
duct some very extensive experiments in what they call "the 
cold curing of cheese." 

As a matter of fact, cheese "ripen" or mature at any low 
temperature at which they may be safely stored. In reality, there- 
fore, cold curing of cheese is simply the cold storing of cheese. 
Cheese is one of the products that improve with age. It is 
not at its best when first made ; in fact it is unpalatable and un- 
healthful when new or "green." It requires "curing" in order 
to make it a healthful and palatable article of food. Under 
ordinary conditions the curing process goes on regardless of 
temperature, but the action is much slower as the temperature 
is lower. The results of experiments which are here given prove 


conclusively that a much better quality of matured cheese results 
when the cheese are placed in cold storage soon after being made. 
It seems that the low temperature prevents the development of 
bad flavors and deleterious gases which injure the flavor and 
texture of the cheese. At the same time it allows the rennet 
which is used in the manufacture of cheese to fulfill its mission 
of curing or ripening. The experiments which are described in 
detail further on need no additional explanation. 

The results of these experiments seem to prove the advisa- 
bility of establishing centralizing stations, which are in reality 
cold storage plants, for the receiving of cheese when first made. 
A plant of this character may be built at any convenient railroad 
point and the cheese from a number of different factories hauled 
thereto at frequent and regular intervals. They are then placed 
under suitable temperature and other conditions and are ready for 
immediate shipment at any time. The advantage of this method 
over the old factory system of allowing the cheese to remain on 
the curing room shelves for a time is that the flavor is improved, 
shrinkage reduced to a minimum and the cheese are protected 
from exposure to hot weather, which is one of the worst things 
that the cheese manufacturer has to contend with. Appreciating 
this difficulty, the sub-earth duct system has been adopted by 
some of the more progressive factories. This is simply an air 
duct running underneath the ground through which circulates 
air which is introduced into the curing room. In passing below 
the surface of the earth, the temperature of the air is reduced to 
60° to 65° F. and the temperature of the curing room is there- 
fore modified during extreme warm weather. It was found that 
this system in many cases had the disadvantage of causing cheese 
to mold badly and no doubt it will be abandoned in favor of 
the cold storage or cold curing method. There is an advantage 
in having cheese brought to a central cold storage or curing 
station in that it is easier for buyers to inspect and brings the 
cheese all into a market center as it were. There is no reason 
why they should be out of possession of the salesman any more 
with this system than they would under the old method. Co- 
operation and consolidation will enable cheese manufacturers to 
realize much better prices for their product, owing to improved 
quality, if they will but adopt the cold storage system instead of 


the old-time curing room method. A large part of the expense 
of a central cold curing station would be paid by the saving 
effected at the factory in not being obliged to provide for shelves 
and curing room space. 

The best refrigerating system for use in connection with 
cold curing will depend upon the section where located and local 
conditions to a large extent. In cooling with air circulating in 
direct contact with ice, a temperature below 40° F. cannot be 
depended upon and as experiments demonstrate that cheese cured 
at a temperature of 30° to 35° F. are of a better flavor and 
texture, it is evident that some system which will produce a 
lower temperature would be advisable. In addition, the humid- 
ity of a room cooled directly from the ice is very high (in other 
words, very moist). It has been demonstrated that the relative 
humidity of such a room when used for the cold curing of cheese 
would be at times somewhat above 90 per cent. These condi- 
tions are very favorable for the growth of mold. The direct ice 
system therefore is not advisable for the reason that sufficiently 
low temperatures and regulation of humidity cannot be obtained. 
The gravity brine system cooled with ice and salt, described else- 
where in this book, is recommended as a system which will con- 
trol temperatures, and in connection with the chloride of calcium 
process, also described elsewhere, the humidity of the room may 
be regulated to any desired degree. In situations where natural 
ice cannot be obtained cheaply, the use of refrigerating machin- 
ery is advisable and the temperature and humidity can thereby 
be controlled in the same way as with the gravity brine system. 


The prevalent opinion among cheese dealers has always 
been that low temperatures, varying from 35° to 50° F., or there- 
abouts, resulted in the production of an inferior quality of cheese, 
in comparison with that from 60° to 70° F. Xo carefully con- 
trolled experiments bearing on this problem have been recorded 
earlier than those undertaken by Babcock and Russell at the 
Wisconsin Agricultural Experiment Station, and described in 
the fourteenth (1897) annual report of that station. The results 

•Extracts from Bulletin No. 49, Bureau of Animal Industry, U. S. A^r. Dept., giving 
results of experiments conducted under the directions of Henry E. Alvord, Chief of Dairy 
Division. More detailed information may be obtained by consulting same. 


of those tests showed that cheese placed at refrigerator tempera- 
tures (45° to 50° F.), directly from the press, was of superior 
quality as to flavor and also as to texture, and that such cheese 
was wholly free from any bitter or other undesirable taints. 

In connection with their studies on the influence which 
galactase and rennet extract exert on the progress of cheese 
ripening, the same investigators later employed still lower tem- 
peratures (25° to 30° F.). Cheeses were kept at these exces- 
sively low curing temperatures for a period of eighteen months. 
The quality of these cheeses, cured as they were below the freez- 
ing point throughout their whole history, was exceptionally fine, 
and emphasized still more than the previous experiments did the 
fact that the ripening of cheese can go on at much lower tempera- 
tures than has heretofore been considered possible. 

These results led to an extended series of experiments, in 
which cheese made on a commercial scale was cured at a range 
of temperature from below freezing (15** F.) to 60° F. — a point 
which common practice has now accepted as the best obtainable 
temperature that can be secured without the use of artificial 
refrigeration. [No doubt the term "artificial refrigeration" as 
here used means cooling by any means other than natural earth 
or air temperature, and not the generally accepted meaning, viz., 
refrigerating machinery. — Author.] 

In these experiments (consisting of five series made at in- 
tervals throughout a period of two years) 138 cheeses were used, 
for which 30,000 pounds of milk were required. These experi- 
ments were upon a scale which represented commercial condi- 
tions, and therefore obviated the objection which is often urged 
in commercial practice against the application of results derived 
simply from laboratory experiments. 

The Ontario Agricultural College began experiments on the 
cold curing of cheese in April, 1901. As a result of these tests, 
the conclusion was drawn that the cheese cured at low tempera- 
tures (37.8° F.) was much superior to that cured in ordinary 
curing rooms (average temperature during season 63.8® F.). 
Mr. R. M. Ballantyne, a prominent cheese expert, said of this 
cheese that "they (the merchants) universally expressed surprise 
at the condition of the cheese that was put into cold storage at 
the earliest period (that is, directly from the press), as they 


expected to find the cheese still curdy and probably with a bitter 
flavor."* If this experiment is borne out by other experts, it 
would appear as if the best way to handle hot-weather cheese 
would be to ship it to the cold storage directly after making, 
and this would certainly mean a great revolution to the trade. 

A considerable number of experiments have also been made 
at other stations (Dominion government tests and New York 
State and Iowa experiment stations), where somewhat lower tem- 
peratures were used than those which are noimally employed for 
ripening. The results obtained all show an improvement in 
quality that becomes more marked as the temperature is reduced. 

In order that a much larger experiment might be instituted, 
covering the different types of cheese as represented by eastern 
as well as western manufacture, Drs. Babcock and Russell, of the 
Wisconsin Station, presented this matter for consideration to the 
Dairy Division of the Bureau of Animal Industry. As a result 
of this proposal the officers of the New York Agricultural Ex- 
periment Station were also consulted and plans perfected for the 
cooperative experiments conducted simultaneously in Wisconsin 
and New York. [The eastern experiments are not given here 
as the results differ in detail only, general conclusions being the 
same in both series of experiments.] It should be noted that 
it was so late in the season of 1902 when the arrangements for 
this work were completed that it was impossible to obtain favor- 
able conditions in all respects. 

In addition to the influence which a range in temperature 
exerts on the quality of cheese, as determined by flavor and tex- 
ture scores, instructions were also issued to secure data regard- 
ing the loss in weight which the different lots of cheese suffered 
at the different temperatures. The commercial quality of the 
product was to be determined by a jury of experts who were 
thoroughly in touch with the demands of the market. Although 
the effect of coating cheese with paraffin soon after being taken 
from the hoop was not at first proposed as a part of this work, it 
was finally included. 

The reasons for selecting 40"*, 50°, and 60° F. as the tem- 
peratures to be used in these experiments are fully given on a 
later page. It may be assumed that the advantages of a cool 

^Bulletin No. lai, Ontario Agricultural College, June, 1902. 


and even temperature in curing Cheddar cheese have been already 
established in preference to a warm temperature or to very vari- 
able conditions which frequently include periods above 70° F. 
and sometimes much higher. As already stated, 60° F. or there- 
abouts is regarded as the lowest temperature practicable without 
artificial refrigeration; this may therefore be taken as fairly 
representative of what may be called a "cool" temperature for 
curing cheese. And rooms held at 40** and 50° F. were selected 
as representative of a "cold" temperature for curing, or compara- 
tively so. It is thus hoped to emphasize by these experiments 
the distinction between cool curing and cold curing. 

The cheese for these experiments was purchased by the 
United States Department of Agriculture, which also paid all 
expenses of transportation and storage and for the experts who 
made the periodical examinations. The two experiment stations 
selected the cheese, arranged all details of storage and examina- 
tion, supervised the work throughout, performed the chemical and 
other incidental scientific work, kept the records, and reported 

Each of the reports, prepared by the two experiment sta- 
tions participating in this work, treats the same general subject 
and sim.ilar lines of experiment and observation from its own 
point of view. The reports therefore differ in many respects, 
and yet they may be easily compared upon all essential points. 
Both support the same general conclusions as to the advantages 
of curing cheese at low temperatures, summarized as follows: 

I. — The loss of moisture is less at low temperatures, and 
therefore there is more cheese to sell. 

2. — The commercial quality of cheese cured at low tempera- 
tures is better, resulting in giving cheese a higher market value. 

3. — Cheese can be held a long time at low temperatures 
without impairment of quality. 

4. — By utilizing the combination of paraffining cheese and 
curing it at low temperatures the greatest economy is effected. 


For the purposes of this experiment Chicago would natur- 
ally have been chosen as a curing station, but it was found dif- 

♦Conducted by S. M. Babcock and H. L. Russell, assisted by U. S. Baer. all of 
the Wisconsin Agricultural Experiment Station. 


ficult to make arrangements for the range of temperatures de- 
sired. Suitable arrangements, however, were made at the cold- 
storage warehouse of the Roach & Seeber Co., Waterloo, Wis., 
where rooms were fitted up and the desired temperatures secured. 

As Wisconsin is the leading cheese-producing state of the 
west, the bulk of the product selected for experiment was of 
the type of cheese manufactured in this state. In order, how- 
ever, to cover more thoroughly the cheese-producing territory 
of the west samples were also secured from a number of the 
neighboring states. In this way all types of American cheese 
were obtained, ranging from the firm, typical Cheddar cheese, 
suitable for export, to the soft, open-bodied, moist cheese, in- 
tended for early consumption. For convenience we may group 
these various lots of cheese under three different types, as 
follows : 

I. — Gose-bodied, firm, long-keeping type, suitable for export 
trade (typical Cheddar). 

II. — Sweet-curd type. 

III. — Soft, open-bodied, quick-curing type, suitable for early 

Type I represents the class of cheese that is especially manu- 
factured in Wisconsin, while, as a rule, type III represents the 
kind of cheese that is chiefly made in Michigan. The repre- 
sentatives of the sweet-curd type were taken from Iowa and 
Illinois, although this class is made to some extent in all sections. 

In having the cheese made at these various factories direc- 
tions were given for the use of a uniform amount of rennet and 
salt. Color was left optional for each maker to follow his cus- 
tomary practice. The use of 3>4 ounces of Hansen's rennet 
extract and 2y2 pounds of salt per i,ooo pounds of milk was 
recommended in each case with the exception of the smaller 
cheeses (dairies and lo-pound prints), which were salted at the 
rate of 234 pounds per 1,000 pounds of milk. The cheese was 
made from September 26 to October 4. The condition of the 
milk was influenced in several instances by the fact that severe 
frosts had occurred in some sections, which injured the quality 
of the product. This was particularly true in the case of the 
Alma cheese, which was in consequence somewhat tainted. The 
milk from which the Iowa cheese was made was also reported as 



of inferior quality. The Michigan goods were too high in acid, 
and were cooked low, making a soft cheese, which was quick- 
curing and which kept poorly. 

Where it was necessary to secure cheese from such a wide 
range of territory it was manifestly impossible to expect that the 
curing could be carried out as satisfactorily as if it had been 
done at or near the factories. The varying period of transit to 
which the cheese was subjected, with no especial temperature 
control, affected, of course, the initial stages of curing, but the 
conditions of the experiment prevented the carrying out of im- 
mediate installation of the cheese in the cold curing rooms, es- 
pecially in the case of those made outside of Wisconsin, although 
the shipments w^ere made in October, when the temperature 
range was moderate. 


The cheese was weighed and put in the respective rooms as 
soon as received at Waterloo. It was stored in boxes during 
the curings as is the custom in the handling of cold-storage goods. 
The temperatures at which it was desired to hold the cheese for 
curing were 40°, 50**, and 60° F. These points were selected 
for the following reasons: In our previous experiments we had 
found that the character of the cheese cured at the lower tem- 
peratures (40° and 50°) was much better than that produced at 
60° F. Perhaps it would have been better for the purpose of 
the experiment if the cold-cured cheese could have been com- 
pared with the same make of cheese cured under the widely 
variable conditions which prevail in most factories, where often 
the maximum temperature is in the neighborhood of 80** F. and 
the fluctuation is 20° or rriore ; but we have made this comparison 
with the very best conditions that obtain in factories provided 
with subearth ducts and other means of temperature control. 
In such cases a temperature of 60° F. can be maintained with a 
fair degree of constancy. The experiments, therefore, compare 
the cold-curing process with that of the best prevailing con- 

The temperatures actually maintained varied only slightly 
from the chosen points, and in the two colder rooms were re- 
markably uniform. The 60** room was subject to somewhat 


wider fluctuations, but was much more uniform than is obtained 
in summer where no artificial refrigeration is practiced. 


It would have been advisable to have the cheese examined a 
■considerable number of times by the commercial judges, but it 
was impossible to carry out this test so frequently. The tests 
were therefore arranged to come at those periods which would 
give the judges the most accurate idea of the character of the 
cheese held at the diflferent temperatures. 

As a jury of commercial experts, representing the different 
markets, the following gentlemen were selected : C. A. White, of 
Fond du Lac, resident representative in Wisconsin of a leading 
dairy produce house of New York; T. B. Millar, of London, 
Ontario, a cheese expert and large buyer for the export trade, 
and John Kirkpatrick, a member of a leading produce firm of 

For the jury trials representative cheese were taken from 
storage and shipped by refrigerator service to Chicago, where 
they were submitted to a thorough examination by the commer- 
cial judges. The first of these commercial scorings was made 
when it was found that the 60° product was ready for market. 
This test was made on January 6, 1903. Another test was made 
on March 23, when the cheese was about 7 months old. 

It might at first thought seem preferable to have had the 
cheese sold in the open market and thus secured a strict commer- 
cial valuation on the product, but, as everyone knows, a consider- 
able variation in quality may exist without an appreciable differ- 
ence being made in the market price. Then, too, the inevitable 
fluctuations in the market price would render comparisons at 
different periods untrustworthy. To obviate these difficulties the 
cheese was scored on the basis of a standard price (13 cents). 
The fact that but few of the cheese reached this standard should 
not be interpreted as indicating a poorer quality than the average 
market product, for the cheese was adjudged by the jury to be 
superior in quality ; but the price was in part determined by the 
market appearance of the goods, which was somewhat inferior 
because of the fact that they had been box-cured and had received 


practically no care in curing, as the curing station was located at 
a distance from Madison. 

The scores of the commercial jury were supplemented by a 
series of scores made by Mr. Baer which covered the entire his- 
tory of the cheese from the time it was received until its final 
disposition. In this study it was possible to follow more closely 
the course of the ripening. 



The losses in weight which cheese undergoes in the curing 
process is a matter of such practical importance that it is ad- 
visable when possible to accumulate data relating to it. This is 
all the more important in this connection because no studies have 
yet been reported on cold-cured cheese, and it was therefore 
deemed advisable to keep a record of the losses in weight so 
that the shrinkage at these lower temperatures might be com- 
pared with those which normally obtain at the best temperatures 
now employed. The average shrinkage under existing curing 
conditions in the majority of factories results in a loss of 5 to 7 
per cent for the first thirty days, with a gradually diminishing 
rate for longer curing periods. This results in a heavy tax to 
the producer, and any factor which reduces these losses increases 
thereby the total receipts from the milk produced. 

There are a number of factors which modify the rate at 
which a cheese loses its water content during the course of ripen- 
ing. The following factors are known to exert a more or less 
marked influence, although it is impossible to arrange them in 
order of their relative importance, as they are always inter- 
dependent : 

I. — Temperature of curing room. 

2. — Relative humidity of air in curing room. 

3. — Size and form of cheese. 

4. — ^Moisture content of the cheese. 

5. — Protection to external surface of the cheese. 

The influence of temperature is closely connected with the 
relative humidity of the curing room ; but, in addition to the 
effect which the higher temperatures exert on this factor, it 
should be observed that water evaporates more rapidly at a high 


than at a low temperature, even though the relative humidity 
remains the same. The more potent influence of temperature is, 
however, the eflfect which varying degrees of heat exert on the 
relative humidity of the atmosphere. A fall of 20° F. from 
ordinary air temperatures practically doubles the relative humid- 
ity, provided the point of saturation is not passed. As the 
average relative humidity of the air is generally over 50 per 
cent, it therefore follows, in cold-curing rooms supplied with 
outside air, the temperature of which is from 30° to 40° I*", 
higher in summer than the inside temperatures, that the air of 
these rooms is practically saturated, thus greatly reducing the 
loss of moisture from the cheese. [Conclusions so positive as 
these are not warranted. Temperature and humidity are not 
necessarily closely related. Water evaporates more rapidly at 
high temperature because the capacity of air for moisture is 
increased with its temperature, but it does not necessarily follow 
that the humidity is increased as the temperature is reduced, and 
a room in which the air is nearly saturated with moisture seldom 
exists. If it did it would be a bad place to store cheese because 
mold would grow rapidly. See chapter on ''Humidity."] 

So far as the cheese itself is concerned, the moisture of the 
room may be materially altered by the way in which the cheese 
is handled during the curing process. If the cheese is shelf- 
cured, as is the custom in most factories, the surrounding air 
more nearly approximates the average relative humidity of the 
entire room than is the case where the goods are box-cured. In 
the latter case the air is more nearly saturated, as is shown by the 
greater liability to mold and rind-rot. 

This point is well shown in a series of observations on the 
relative humidity of the air in a box containing a cheese placed 
directly therein from the press. 

A factor which is frequently overlooked is the varying mois- 
ture content of the cheese. The more moisture there is left in 
the cheese the more rapid the evaporation. The varying mois- 
ture content of different types of cheese is determined by the 
temperature at which the curds are cooked, the time of exposure, 
and the acidity of the curd. A cheese in which the acidity is 
developed is materially drier than a sweet-curd cheese. Salt also 
has a tendency to diminish the water content. In the foregoing 


cases the cause of this diminution in moisture is due to the 
shrinking of the curd particles under the influence of these fac- 
tors. An increase in fat lessens the drying of the curd. Much 
loss of moisture can also be prevented by coating the cheese with 
paraffin, a practice which is now coming into very general use 
for the prevention of mold and to lessen shrinkage in weight. 


In these experiments the first careful weighings were made 
when the cheese was received at the cold-storage plant in Water- 
loo. The cheese was shipped from the factories directly after it 
was removed from the press, but was in every case several days 
upon the road. In no instance was the interval between making 
and installing in cold-curing rooms less than five days, and it 
ranged from this up to seventeen days with one lot from Michi- 
gan, which was delayed in transit. During this period, which 
was in early October, the cheese was subjected to varying condi- 
tions of temperature and exposure. In a few cases boxes were 
broken, and in other instances the cheese was delayed at points 
of transfer. It was impossibte to obviate these difficulties, as 
the cheese was purchased at distant points in order to secure 
representation from a wide range of territory and from different 
types of cheese. This variation in initial drying changed, of 
course, the rate of loss when cheese was placed in cold-curing 
rooms, so that this factor must be taken into consideration in 
studying the data presented below. 

The losses reported here cover those only which took place 
in the cheese after it had reached the cold-curing rooms, but 
careful records have been kept for the entire curing period; and 
these data, we believe, are of sufficient importance to warrant full 
consideration in this connection. 


The cheese was all weighed on counter scales, weighing ac- 
curately to fractions of an ounce. In order to check the accuracy 
of the weights, each cheese was weighed separately and the 
weight recorded : then the whole lot was weighed collectively. 
As these weights agreed within a few ounces, they show the 
accuracy of the weighings. For practical purposes it is desirable 


to know the losses which occur for stated periods. It was, how- 
ever, impracticable for all of the cheese to be weighed at exactly 
the same intervals, as it was put in storage at different dates, but 
it was designed to secure at least three weighings for the first 
month of storage, two weighings for the second, and at about 
monthly intervals thereafter. If these data are charted, it is 
possible to deduce an estimated loss for any stated period, and 
in doing so we have selected the following intervals as being 
those concerning which data would be most frequently desired. 
For this purpose ten, twenty, thirty, sixty, ninety, etc., days have 
been selected. 


In this work the attempt was made to hold the cheese at 
40°, 50°, and 60° F. The actual temperatures secured averaged 
36.8°, 46.9°, and 58.5° F. The variation in temperature in the 
two lower rooms was practically negligible, as it was only 2° to 
2^^. The temperature of the 60° room oscillated somewhat more 
(4° F.), but was very much more uniform than ordinary factory 
curing rooms. 

Hygrometric data were not secured during the whole 
period, as it was at first thought that a saturated atmosphere 
would prevail where the cheese was box-cured, but during the 
course of the experiments it was noted that the 50** cheese was 
not molding as much as was that at 40° and 60°. This fact could 
only be explained by the assumption that a less humid atmosphere 
was present in the case of the 50° room. [See previous remarks 
on temperature and relative humidity.] 


As there are several factors which affect the rate of shrink- 
age which the cheese suffers in curing, it will be desirable to 
discuss the data collected under several heads. The conditions 
of the experiment were such as to temperature that an espe- 
cially favorable opportunity was had for the study of the influence 
which this factor exerts on the cheese. It is, of course, neces- 
sary in a study of this sort to have the cheese uniform in size. 
The moisture contents of the cheese can not, of course, be made 
alike, but in this study the cheese of the same type have been 


grouped together — that is, as firm Cheddars suitable for export 
and softer, moister cheese intended for home trade. 


To study the rate of loss of Cheddar cheese when kept at 
different temperatures, 129 flats were selected from nine different 
lots of cheese made by six different makers. These were exposed 
at three different temperatures, which averaged, respectively, 
36.8**, 46.9°, and 58.5° F. The results obtained were calculated 
upon the number of cheese which were subjected to stated weigh- 
ings. During the experiments much more data were collected on 
the lower temperatures than on the 60° lot. This was regarded 
necessary, as up to this time we have no published data on cheese 
cured at so low a temperature. 

For purposes of convenience the different lots of cheese 
were divided into three types, depending upon their character: 

I. — Firm-bodied cheese (export type), of Wisconsin. 

II. — Sweet-curd type, as represented by the Iowa and 
Illinois makes. 

III. — A very moist, soft type, suitable for home trade 

The general conclusions arrived at were: 

I. — The losses sustained by the different lots were very 
much less at 40° F. than at either of the other two temperatures. 
For a ninety-day period the losses of the 40° cheese ranged from 
I to 1.4 per cent, while the 50° and 60° product shrunk from 3.4 
to 4.5 per cent for the same time. In other words, by the use of 
the lower temperature for curing practically two-thirds of the 
losses which occurred at the temperatures of 50° and 60° F. were 
prevented. If these results are compared with what happens 
under ordinary factory conditions, the loss at these low tempera- 
tures for a period of ninety days (the minimum curing period 
recommended) will not be more than one-fourth of that which 
obtains under average factory conditions when the cheese are 
held for a period of about twenty days. The saving for any such 
factory making 500 pounds of cheese daily would amount to at 
least 15 pounds of cheese (or $1.50) per day as an average for 
the season, and considerably more than this for cheese made 
during hot weather. This saving in itself would go far toward 


meeting the extra expense of lower temperature curing, even if 
the product was no better than that cured at higher temperatures. 

2. — The differences between the cheese cured at 50° and 60° 
F. are not so marked as between 50° and 40° F. It is quite prob- 
able, as before mentioned, that the 50° room was somewhat drier 
than the 60° (as shown by the lessened mold growth), and hence 
the rate of loss was abnormally increased in this room. [The 
reason why evaporation is less at the lower temperatures is not 
necessarily owing to higher relative humidity, but to the lesser 
capacity of the air for moisture at low temperatures. — Author.] 

3. — If the firm Wisconsin type is compared with the softer 
variety, as shown in types II and III, it appears that the losses 
are considerably less, especially at the higher temperatures, al- 
though this difference is not so observable at 40° F. 

4. — The data referred to above showed a marked saving in 
losses where the cheese was cold cured, but in these experiments 
it must be remembered that the cheese was subjected to higher 
temperatures during transit, and hence dried out somewhat more 
than would have occurred if put in storage as soon as removed 
from the press; also, that this cheese was box-cured, and there- 
fore under conditions which prevented rapid evaporation. Under 
other conditions the losses would have been greater than repre-' 
sented here, and the difference in the rate of loss between the 
different lots wider than reported above. This would still fur- 
ther increase the saving. 

It must be remembered that the entire loss in weight during 
the curing of cheese is not due to evaporation. A cheese in cur- 
ing is constantly breathing out carbon dioxide the same as any 
living organism, due to the development of microorganisms 
(bacterial growth within the cheese as well as molds on surface). 
Aside from these biological factors, it has been shown by Van 
Slyke and Hart* that profound proteolytic decompositions also 
give rise to an appreciable amount of COg. With cheese at 60° 
F., in which external mold growth was suppressed, they found 
a loss of approximately one-fourth of i per cent in ninety days. 
In our cold-cured cheese, copious mold development occurred, 
and hence the losses of carbon from the cheese due to this growth 
would be considerably greater than if no such growth occurred. 

•Bulletin No. 231, New York State ARricultural Experiment Station, p. 36. 


With the nearly uniform rate of shrinkage shown in these cold- 
cured cheese, regardless of size, it is quite problematical whether 
this loss in weight may not be chiefly due to the operation of the 
foregoing factors. If this is so, we may consider such losses as 
absolutely unavoidable under normal conditions, for the action 
of microorganisms which can not be suppressed will inevitably 
result in the production of some volatile products. [This inter- 
esting deduction is supported by the tests by the author and others 
on the keeping of eggs in sealed packages. See chapter on **Eggs 
in Cold Storage."] 

At the temperatures of 50° and 60° F., where the relative 
humidity was below saturation, the factor of evaporation is 
apparent and is inversely related to the size of the cheese. From 
a practical point of view, it is worth noting that the losses in 
both sizes of cheese cured at 60° F. are approximately 50 per 
cent more than they are in the cheese ripened at 50° F. 


Within the last few years the custom of coating the cheese 
with an impervious layer has been suggested, with the object 
mainly of preventing the development of mold. For this pur- 
pose paraffin has been found to be the most suitable agent. The 
application of such a layer to the cheese not only prevents the 
growth of mold spores by excluding the air, but materially re- 
tards the rate at which the cheese loses its moisture. Paraffined 
cheese then dries out much more slowly than the untreated prod- 
uct, and the application of this method is of particular service in 
the handling of the smaller types of cheese, which have a rela- 
tively larger superficial area exposed to the air. 

In the paraffined cheese at 40° F. the losses were reduced 
practically to a minimum, as was also the case with the unparaf- 
fined at this temperature. As evaporation would certainly be 
lessened in the paraffined lot, the uniformity of loss between these 
and the unparaffined still further substantiates the view advanced 
earlier that these losses are not so much due to shrinkage from 
evaporation as they are to metabolic activities of organisms and 
possibly chemical transformations within the cheese. 



Originally it was planned to have the cheese judged by com- 
mercial experts, but it was found impossible to arrange for a 
sufficiently large number of such tests to closely follow the pro- 
gressive changes which occurred in the course of the ripening 
of the cheese. Hence, in addition to the examinations made by 
the jury of commercial experts, the cheese was carefully scored 
at Waterloo by Mr. Baer at frequent intervals. 


Type I was represented by four different lots of Wisconsin 
cheese. All of them were well-cooked, firm-bodied, slow-ripen- 
ing cheese that may be regarded as typical Cheddars. In one case 
the milk from which the cheese was made was evidently tainted, 
as the cheese was slightly off at the outset. 

The results of these periodical scores by Mr. Baer show that 
good cheese was produced at all temperatures in the first three 
lots. Naturally that cured at 60° F. developed more rapidly 
than the goods cured at lower temperatures^ but it should be 
noticed that even at this temperature some of the firm-textured 
cheese went off in five months. At 50° and 40° F. the cheese 
was about six weeks to two months behind the 60° in develop- 
ment, but in time it reached as high as the 60° lot, and generally 
of a better quality, and kept this maximum condition much longer 
than the 60°. This enhanced keeping quality was more pro- 
nounced at 40° than at 50** F. 

In the lot made from tainted milk the imperfect condition 
was pronounced at all temperatures, but was more prominent 
at 60° than below. 

In studying the scores by Mr. Baer, it is possible to combine 
the numerical scores of the four different lots of Wisconsin 
cheese belonging to the same type and so obtain a set of averages, 
as to flavor, texture, and price, which indicate clearly the progress 
of the curing of these various lots at the different temperatures. 

The variation in flavor observed at the different tempera- 
tures is more marked than any other characteristic. It appears 
that at the higher temperatures the flavor is more developed dur- 
ing the earlier ripening stagey, but as the cheese increases in age 


the quality of the flavor at the higher temperatures deteriorates 
more rapidly than in the cold-cured goods. At the end of five 
months the 40° was still improving, and even at this time was 
higher than at any period with the 50° and 60°. At the end of 

Cheese at top cured at 40°, in middle at 50", and at bottom at 60". 

eight months the cold-cured cheese was still of excellent quality, 
and showed no signs of deterioration. 

The texture of the cheese followed quite closely a develop- 
ment similar to that noted above. In the earlier stages the 60° 
had the highest score, but it reached its maximum in three 
months, while the 50"^ and 40° continued to improve up to the 



end of the test, and was higher in the 40° at this time than at any 
time in the 60°. 

Cheese cured at 40" on left and cheese cured at 60° on right. 

The beneficial effect of cold-curing on this firm type of 
cheese is strikingly apparent from the above data. Not only was 
this cold-cured cheese free from any bitterness or taint incident 


to the curing process, but it was much improved in texture, as 
is evident from Fig. i, which shows the appearance of cheese 
made from the same vat but cured at approximately 40°, 50°, and 
60° F. When the cheese is cold-cured the body is much closer, 

Cheese cured at 40° on top, cheese cured at 60** on bottom. 

as the curd particles are subject to more pronounced shrinkage at 
higher temperatures, which causes the formation of these irregu- 
lar, ragged cracks. This is perhaps rendered more obvious in 
cheese cured at 40° and 60° F., as shown in Figs. 2 and 3. When 


it is remembered that the results ordinarily obtained in factory 
curing are not anything like as satisfactory as those shown in 
the cheese cured at 60° F., the improvement in quality, as shown 
by the texture of the cheese cured by the cold-curing process over 
that now in vogue, is emphasized still more. 

The 50° cheese stands intermediate between the distinct- 
ively cold-cured product and that obtained under best present 
conditions without artificial refrigeration. Emphasis has already 
been laid upon the fact that a considerable improvement in qual- 
ity is to be expected where a slight diminution in temperature 
is secured over that found in the best type of factory curing now 
in vogue. This system of "cool-curing" — that is, the use of a 
temperature from 52° to 58° F., as recently advocated by the 
Canadian authorities* — stands midway between the cold-curing 
process and the system now most frequently in use. The benefits 
to be gained by this system are evident from the Canadian ex- 
periments, in which 480 pairs of cheese were cured, one of each 
lot being kept at 52° to 58° F., while the other was ripened in 
an ordinary curing room (61° to 70°). Quoting Mr. Ruddick's 
paper, he says that "in every case the cool-cured (cheese) has 
been pronounced the best in quality." 

From the experiments detailed above it appears that further 
improvement in quality is possible if the curing temperature is 
still further reduced (40° to 50° F.). It must be remembered in 
this comparison that the highest temperature we employed is 
much lower than the average factory curing room. The differ- 
ence in quality between cold-cured and ordinary-cured cheese 
would be much greater than that represented in this work. 

The cheese of this type at 60° F. ripened rapidly and showed 
an excellent quality in all lots but one, which was tainted from 
the beginning, but they all passed their prime in three months 
and showed marked deterioration by the end of five months. 

With this type of cheese it must be remembered that the 
quality of the flavor produced at low temperatures is quite dif- 
ferent from that found at 60° F. Cold-cured cheese possesses a 
very mild but perfectly clean flavor, together with a solid, waxy 

*]. A. Ruddick in paper presented at the Ontario Dairymen's Association, January, 



The cheese in Type II is not so uniform in its make-up as 
that of Type I, but it represents that type of American product in 
which less acid is developed than is found in the normal Cheddar 
cheese. This cheese is more open in texture and contains a con- 
siderable number of mechanical and small Swiss holes, as shown 
in Fig. 3. The cheese was somewhat low in flavor, due in all 
probability to the milk and method of manufacture, and not to 
the curing, as this defect was quite as apparent at the lower tem- 
peratures as at 60° F. 

The Iowa cheese was found to be of only fair quality, but 
at all ages was better at 40° F. than at other temperatures, al- 
though the difference is considerably less than it was with the 
firmer Wisconsin type of cheese. 

The Illinois cheese was quite similar to the Iowa lot, but 
the texture of this cheese at 60° F. was considerably more im- 
paired than that obtained at the lower temperatures. 


Type III represents the softer make of cheese intended for 
home trade, and one which cures more quickly, and therefore 
does not keep as long as the firmer Cheddar type. Tliis type is 
represented by four different lots of Michigan cheese made at 
the same factory. They were not of standard quality, but were 
too acid. The first three lots were materially delayed in transit 
and consequently had undergone considerable change before 
being cold-cured. From the detailed data it is evident that lot 
four was the best, and in this lot the 40° and 50° were both bet- 
ter than the 60°. 

In this case the flavor of the four lots was poor, only once 
exceeding 40 points. While the 60° scored higher at one time 
than the cheese at the other two temperatures, the 40° cheese at 
five months equaled the flavor of the higher temperature cheese 
at this time. 

The difference in price of this cheese at three months was 
inconsequential, and from this date the cheese at all temperatures 
fell off rapidly in value. 

All four lots of these Michigan goods were more or less de- 
layed in transit, although lot four was no more so than some of 


the cheese in the other types. But with this moist, quick-curing 
cheese it was much more susceptible to temperature influences, 
and hence was materially impaired before being put in storage. 
This condition, taken in connection with the inferior make (high 
acid), renders this part of the experiment unsatisfactory. 

In the first test the jury consisted of Messrs. White, Millar, 
and Kirkpatrick. In the second test, made when the cheese was 
five months old, one of the judges (Kirkpatrick) was unfortun- 
ately unable to assist. It is therefore impossible to compare with 
each other the average scores secured in these two tests, as the 
judgment of the different members of the jury naturally is not uni- 
form. In comparing, therefore, the course of ripening in the 
three and five months' tests, it will be necessary to correct the 
averages given by eliminating the score of the judge who was 
absent in the second test. 

For purposes of study, however, the two tests can be con- 
sidered independently and the influence of the different tempera- 
tures on the character of the cheese determined. 


When the cheese had been cured for three months, the sam- 
ple cheese which had been tested previously at monthly inter- 
vals by Mr. Baer, was shipped by refrigerator service to Chicago 
and submitted to the jury for examination. 

Type I, In the four lots of cheese which comprised this 
group the 50° product was higher in flavor twice, the 40° once, 
and once the 40° and 50° were alike. In no case, even at this 
age, when the 60° cheese was at its best (as shown by the serial 
examinations made by Mr. Baer), did this cheese reach as fine 
a flavor as at the lower temperatures. 

In texture the 40° lot was ahead twice, once the 50° and 60** 
were alike, and once the 60° was the highest. 

As to price, in no case did the 60° equal the value set upon 
the cheese cured at the lower temperatures, although the differ- 
ence given by the judges was slight. It must be remembered 
that the price assigned by the commercial jury was influenced 
materially by the fact that there is considerable difference in qual- 
ity, even among the best types of cheese, without a corresponding 
difference in price. In the majority of cases, when the cheese 



scored within one or two points of perfect, the price was cut 
from a quarter to a half cent below the market standard (13 
cents), simply because the appearance of the cheese on the sur- 
face (mold, etc.) warranted this reduction from a purely com- 
mercial point of view. The judges were free to admit that in- 
trinsically the cold-cured cheese was of much better quality than 
is usually obtained in the market. This cheese was box-cured 
and received no especial care throughout the experiment: con- 
sequently the exterior appearance of the same had been impaired. 
With proper control this condition could have been entirely 
obviated, as we have been able to show repeatedly where cheese 
was cold-cured under our direct supervision. 

Type II. In this type, in which less acid was developed, 
little or no difference was observed in the Iowa goods ; but in the 
Illinois cheese the 40® product had a better flavor and texture 
than the cheese cured at 50° or 60® F. Fig. 4 shows the appear- 
ance of the Illinois cheese cured at the three temperatures when 
three months old. 

Type III. This type is represented by four different lots 
from the same factory. All of the lots were highly acid and were 
of somewhat inferior make. Then, too, tbe earlier lots were de- 
layed in transit from the factory to the curing station, so that 
the results of the experiment should not be considered as neces- 
sarily typical of the cold-curing process. In this group of four 
tests the 50^ goods were ahead twice on flavor, the 60° once, and 
once the 40° and 60° were alike. In texture the 50** was highest 
three times out of four. 


The cheese was examined at this date by the commercial 
judges, as it was thought that the highest temperature cheese 
(60°) had reached its maximum condition. It was naturally ex- 
pected that the 60° product at this time would rank higher in 
quality than the cold-cured goods. 

From this it appears that the 50° cheese was superior in 
flavor and texture, not only on the basis of the total scores, but 
also as to the number of times they ranked highest or equal to the 
cheese cured at either of the other temperatures. This test was 



made before the 40° goods were marketable, but even at this 
time this cheese compared favorably with the 60° product. 


The second commercial scoring was made at the end of five 
months, at which time it was thought that the cold-cured goods 

Cheese at top cured at 40«, in middle at 50", and at bottom at 60*', 

could best be judged from a market point of view. The results 
of this scoring follow: 

Type I. In the four lots tested of this firm-bodied cheese, 
the 40° was highest in flavor three times and the 60"^ once. 
Averaging the total scores show^s that the 40° cheese scored 2.8 
points higher than the 60°, and even the 50° was 1.6 points above 


the cheese held at what has been considered ideal curing con- 

In texture the 40° was highest twice, while in the other 
cases the scores were equal. Numerically, the average texture of 
the 40° was nearly a point above the 60*". At this age the 60° 
goods began to show signs of deterioration, while the cold-cured 
goods kept much better. 

Type II. In this test one lot of the 60° goods (Iowa) was 
mislaid in transit, and hence was not tested, but in this case the 
40° was 2 points above the 50° in flavor, and i point on texture. 
In the Illinois cheese but little difference was observed. 

Type III. In this softer cheese, twice the 40° scored high- 
est in flavor, the 50° and 60° once each. On texture the 40° 
scored highest twice, the 50° once, and the 50° and 60° tied once. 


In this test the average score, as well as the number of times 
any lot has scored the highest, shows that the 40° cheese was su- 
perior to those at either of the other temperatures, while at this 
age the 60° cheese showed that it had passed its prime. 


It is important to compare the scores of the commercial 
judges made at the first and second jury trials, as in this way it 
is possible to study the keeping quality of the cheese cured at 
different ternperatures. Unfortunately one of the judges could 
not be present at the second test. Therefore the judgment of the 
other two has been used in comparing the data of the two tests. 

Type I. With reference to flavor, type I showed its better 
keeping qualities, inasmuch as it held its own at 40° F., while at 
50° F. the cheese had deteriorated 2 points and at 60** F. 2.9 
points. The texture improved at all temperatures as the age in- 
creased, but was much more pronounced (over a point) at 40° 
than at 50° or 60° F. This improvement in flavor and texture 
is also reflected in the enhancement in commercial value. The 
40^ gained 0.2 cent per pound in three to five months, while the 
50° fell off 0.1 cent and the 60° 0.2 cent per pound. Thus in all 


ways the advantage of cold curing is evident on this firm, solid 
type of the Winconsin cheese. 

Type II. In this type, in which less acid was developed than 
in the typical Cheddar type, the deterioration in flavor was less 
at 40° F. than at either 50° or 60° F. In texture, however, all 
scored lower at five months, the data showing a wider difference 
at 40° F. than at the other two temperatures. In price, how- 
ever, the cheese was considered to be worth 0.2 cent per pound 
more at 40°, while the 60° cheese had depreciated 0.7 cent. 

Type III, In the softer Michigan make, in which more 
rapid deterioration would be expected, the falling off in flavor 
was 2 points at 60° F. as against i.i points at 40** F. In texture 
the 40** improved 0.4 point, while the other two depreciated 0.8 
and 0.3 point, respectively. In price, all these goods were of less 
value at five months than at three, but they had depreciated 0.5 
cent at 60° and only o.i cent at 40° F. 

Summarizing the above, there can be no question but that 
the keeping quality of all of these various types of American 
cheese is improved by curing them at these lower temperatures. 
This is more evident with the firm, solid Wisconsin type of Ched- 
dar than with the softer, quick-curing goods ; but even these can 
be held with less deterioration at these temperatures than is pos- 
sible under present curing conditions. 


As the three different types of cheese represented in these 
experiments varied so much in character, it will be fairer to 
state the conclusions with relation to each separately. The scores 
on these lots of cheese were made separately by our own cheese 
expert throughout the whole curing period, and also at stated 
intervals by the commercial judges. 

Type I. At 60° F. flavor developed more rapidly than at 
lower temperatures, but the maximum score at this temperature, 
as indicated by Bacr, was equaled or exceeded by the maximum 
score at 50° or 40° F. In the scoring made by the commercial 
jury the 50° averaged 0.6 point higher than the 60°, when cheese 
was three months old. When five months old, the 40° was 2.8 
points higher than the 60°, and the 50° 1.6 points higher. 


In texture the course of development was quite the same, 
the judges scoring the 50° ahead at three months, but at five 
months the 40° averaged nearly a point higher than the 60°. 

Type IL In this low-acid cheese the course for ripening 
followed the same rule as in the above type, although this cheese 
was inferior in quality to the preceding type. 

Type III. The results on this quick-curing type of cheese 
were affected by the delay in transit, which permitted of a con- 
siderable degree of ripening before the cheese was put in the 
curing rooms. In this type of cheese the improvement was less 
marked, but when the enhanced keeping quality is considered, 
the cold-curing process was found to be advantageous even under 
these advanced conditions. 


With the use of lower temperatures for curing, a higher 
degree of saturation of the atmosphere is always found, which 
greatly promotes the development of mold, and this growth in- 
jures the salability, though not the quality, of the cheese, and 
hence many attempts have been made to overcome the difficulty. 
[The statement that the lower the temperature the higher the 
relative humidity cannot be allowed to stand in the light of pres- 
ent information. Further, mold is checked by the lower tem- 
perature. See chapter on ** Humidity."] The most efficient 
method yet proposed is to coat the surface of the cheese with an 
impervious layer, which, by excluding oxygen, prevents develop- 
ment of molds. For this purpose the cheese are immersed in 
a bath of melted paraffin, which, upon cooling, adheres closely 
to the surface. While this effectually accomplishes the desired 
end, it is a question of importance whether the quality of the 
cheese so treated is affected prejudicially or not. It is possible 
to conceive that the retention of all volatile decomposition prod- 
ucts wMthin the cheese might injure the flavor of the product. 

In these cheese-curing experiments it was thought advisa- 
ble to institute a series of trials to determine what influence 
paraffining had on the quality, as shown by the flavor and texture 
scores. For this purpose the cheese which w^as used in the ex- 
periments on shrinkage (La Crosse lot) was scored by Mr. Baer, 


and was also submitted to the experts for scoring at the regular 

It is evident that the difference between the same lot of 
cheese when paraffined or unparaffined is very slight. If the 
course of curing is considered, as is shown by the scores of Mr. 
Baer, which were taken when the cheese was one, two, three, 
and five months old, it is apparent that the application of par- 
affin has not injured either the flavor or the texture of the cheese. 
It will be further noted that in the "daisies'' the unparaffined 
cheese was, with one exception (60°), better at the beginning; 
but throughout the remainder of the curing and to the end of the 
experiment the paraffined improved much more rapidly, arid 
without exception was as good as or better than the unparaffined. 

With the prints the difference in scores was practically negli- 

This same cheese was scored by the commercial experts 
when it was three and five months old, and it should be noted that 
the opinions of these experts coincided quite closely with those of 
Mr. Baer. 

It would be unsafe from these limited experiments to draw 
any general conclusions, but so far as they go these trials show 
that no injurious effect was observed on either the flavor or the 
texture of the paraffined cheese. 


The purpose of the experiments detailed above was to test 
the value of low temperatures for the curing of cheese made under 
widely different but commercial conditions. To accomplish this 
purpose, it was deemed advisable to purchase the product from 
a wide range of territory. This condition rendered it impossible 
to install the cheese in the curing rooms immediately after it 
was taken from the press, and hence the full effect of the process 
is not so evident as would have been the case if the cheese had 
not had any preliminary curing. 

Naturally a comparison of the cold-curing process would 
be made with the conditions most frequently found in factories, 
but in these studies the low temperature cured product has been 
compared with cheese ripened at about 60° F. — a temperature 


which has hitherto been considered as the best for the ripening of 
Cheddar cheese. 


When cheese is cold-cured, the losses due to shrinkage in 
weight are greatly reduced over what occurs under ordinary 
factory conditions. 

I. — Influence of temperature. — Cheese cured at 40** F. de- 
creased in weight in ninety days from i to 1.4 per cent, while 
that cured at 50® and 60** F. lost fully three times as much. This 
saving would be still further increased if comparison were made 
between the results of cold curing and existing factory conditions. 
Under prevailing factory practice cheese is sold at a much earlier 
date than is advisable with cold-cured goods, but the loss under 
present conditions, for even as brief a curing period as twenty 
days, is fully four times as great as has occurred in these experi- 
ments in a ninety-day period (the minimum curing period recom- 
mended) under cold-curing conditions (40 ** F.). This saving 
in a factory making 500 pounds of cheese daily would average 
not less than 15 pounds of cheese per day for the entire season, 
or considerably more than this if only summer-made cheese was 
cold cured. [It seems to the author that undue stress is being 
laid on the great benefit to be derived from a saving in evapora- 
tion or shrinkage in weight. If this loss is saved to the manu- 
facturer the retailer or consumer is the sufferer, because mois- 
ture has no value as food, and the loss of moisture is practically 
all that evaporation means. More importance should be given to 
the improved quality, because the saving in weight comes out 
of the retailer or consumer.] 

2. — Influence of type of cheese. — In these experiments dif- 
ferent types of cheese were used, ranging from the firm, typical 
Cheddar to the soft, moist, quick-curing cheese made for the 
home trade. The losses with the firmer type were considerably 
reduced in comparison with the other, but the conditions to which 
the softer types of cheese were subjected were not as favorable 
(because of initial delays), and hence the losses with these types 
can not be relied upon with such definiteness. As this cheese was 
exceedingly moist, the total losses from the press were undoubt- 
edly greater than here reported. 


3. — Influence of size of cheese. — The size of package ex- 
erts a marked effect on the rate of loss. At ordinary tempera- 
tures, the smaller the cheese the more rapidly it dries out. This 
difference in loss diminishes as the temperature is lowered, and 
in our experiments at 40° F. was practically independent of the 
size. Tliis condition, however, was undoubtedly attributable to 
the relative humidity of the curing room, which at 40° F. was 
100 per cent. 

4. — Influence of paraffin. — By coating the cheese with melted 
paraffin the losses at 60° were reduced more than one-half; at 
50° the saving was somewhat less, and at 40° the losses observed 
on the paraffined cheese of both sizes used were slightly in excess 
of those noted on the uncoated cheese. [Retailers of cheese in 
England have in some cases made strong objection to the par- 
affining of cheese for the reason that they suffer much greater 
loss from shrinkage when cutting up the cheese for retailing. 
From these experiments it seems that the cold-curing of cheese 
has much more to do with preventing loss of weight than par- 
affining. — Author. ] 

5. — As some loss occurs even in a saturated atmosphere, 
where evaporation is presumed not to take place, it implies that 
the shrinkage in weight of cheese under these conditions is not 
wholly due to desiccation, but is possibly affected by the produc- 
tion of volatile products that are formed by processes inherent in 
the curing of cheese. 


6. — The three types of cheese before referred to can scarcely 
be compared closely with each other, as they were so different in 
their make-up and subjected to somewhat different conditions 
during transit. By far the most satisfactory portion of the ex- 
periment is that which relates to Type I, in which the best quality 
of cheese was represented. With these firm, typical Cheddars 
the influence of temperature on curing could best be studieS. 
This cheese was also placed in storage nearer the press tlian any 
of the other types, and hence the test as to the eft'ect of the curing 
temperature was more satisfactory. In this type the 60° cheese 
was of excellent quality and naturally developed faster than the 
cold-cured goods, but in time it was surpassed by the cheese at 


the lower temperatures (50° and 40°), and, when the keeping 
quality of the latter was taken into consideration, it was found 
to be superior in every way to that cured at 60** F. Even when 
the condition of the milk was not entirely perfect, the quality 
of the cold-cured cheese was better, although the original taint 
was not removed. 

With the sweet-curd (type II) and the soft home-trade 
cheese (type III) the eifect of the disturbing influences pre- 
viously noted rendered it impossible to obtain as satisfactory 
results, but, even under these adverse conditions, the 40° and 50° 
cheese generally ranked better than the 60°, and, when keeping 
quality was taken into consideration, was materially better. 

This same cheese was also scored independently by com- 
mercial experts when three and five months old. The results 
obtained conform very closely to those mentioned above, and in- 
dicate the superiority of the cold-cured product (either at 50° 
or 40° ) in comparison with the cheese cured at 60° F. This im- 
provement in quality reflects itself also in the commercial values 
which were placed upon the cheese cured at different temperatures, 
both by our own expert and also by the commercial judges. 

In this low-temperature-cured cheese the flavor was remark- 
ably mild but clean, and was free from all trace of bitterness or 
other taint. The texture was fine and silky and the body close. 

7. — Keeping quality, — The keeping quality of the cold-cured 
cheese far excels that of the cheese ripened at higher tempera- 
tures. The better types of cheese cured at 40° F. were at the end 
of eight months still in their prime, while the 60° cheese had long 
since greatly deteriorated. 

8. — Effect of paraffin on quality. — Portions of two lots of 
cheese w^ere paraffined as they came from the press, but were 
otherwise handled the same as the unparaffined cheese. The 
results obtained showed that paraffining did not prejudicially 
affect their quality at any temperature. As paraffining greatly 
reduced the shrinkage, the beneficial effect of the system is ob- 
vious. The rapid introduction of the method in commercial prac- 
tice further attests its value, 

9. — The production of a thoroughly broken-down Cheddar 
cheese of mild, delicate flavor and perfect texture meets a de- 
mand which is impossible to satisfy with cheese cured at high 


temperatures. Without any question, if the general market can 
be supplied with this mild, well-ripened cheese, consumption will 
be greatly stimulated, not only by increasing the amount used by 
present consumers, but by largely extending the use of this valua- 
ble and nutritious article of food. 

ID. — The improvement in quality of cold-cured cheese, the 
enhanced keeping quality, and the material saving in shrinkage 
due to lessened evaporation are sufficient to warrant a consid- 
erable expenditure on the part of cheese producers in installing 
cold-curing stations. ' 

The principle of increasing cost of equipment to lessen cost 
of production or augment gross earnings is recognized as a sound 
financial method by all large enterprises, and, while the expense 
involved is considerably more than is incurred under existing 
conditions, yet the advantages enumerated more than compensate 
for such expense where carried out under proper conditions. 

II. — This system is particularly applicable where the product 
of a number of factories can be handled at one point, and such 
consolidated curing stations must be established before the cold- 
curing process can be economically introduced. Such stations 
are now successfully used in a number of localities. The greatest 
advantage will undoubtedly accrue from the use of this system 
of curing with summer-made cheese, but the process is equally 
applicable to cheese made at any season of the year. 

author's concluding remarks. 

The foregoing report of the result of experiments by the 
Wisconsin Station demonstrates fully the desirability of low 
temperatures for cheese storing, and for the curing of cheese 
by placing it in a low temperature as soon as manufactured. 
The experiments do not, however, include temperatures of from 
30° to 32'' F., which are now considered best for long period 
storage of cheese. It is desirable that the best temperatures for 
the most successful curing of cheese should be determined and 
additional experiments should be made for this purpose. It is 
practicable to extend the experiments so as to include foreign 
makes as well as the various types of American cheese. 

The cheese business is now practically all handled through 
cold storage, and temperatures ranging from 30° to 40° F. are 


in use. The use of cold storage for the curing of cheese is, 
therefore, not in an experimental stage, and it is to be regretted 
that the experiments of the Department of Agriculture did not 
include temperatures of 30° F. and 35° F. as representing the 
commercial practice of the times, and a still lower range to de- 
termine the possibilities in this direction. 

The initial quality of cheese has much to do with what is 
best for it in the way of temperature while curing or cold stor- 
ing, but nothing positive may be said on this point at the pres- 
ent time, as no results of experiments are at hand as a guide. 
The author recommends that a good average clean-flavored make 
of American cheese be first placed in a temperature of about 40° 
F. After being in storage for a month or two reduce the tem- 
perature gradually so that at the end of two or three months the 
temperature reaches 30° F., which is recommended for a perma- 
nent storage temperature. This temperature is somewhat lower 
than is generally considered best, but if handled as suggested 
better results may be had than at any higher temperature. 




It has been estimated that the total amount of butter pro- 
duced in the United States is about 1,500,000,000 pounds each 
year. It is probable that the amount is in excess of this rather 
than less. The consumption of butter is rapidly increasing and 
the average quality of same is likewise being improved, but it 
is probable that not more than one-half of the butter made reaches 
the consumer in prime condition. The most important reason 
for this is, no doubt, that refrigeration is not employed to a suf- 
ficient extent, or where employed, not intelligently or scientifically 

Though nowadays not of the same importance to the dairy 
as it was before the centrifugal creamers were invented, yet in 
our climate ice or refrigerating machinery is indispensable to 
the production of fine butter. To fully control the process, the 
butter maker must be able to heat and cool the cream at will, 
and the butter often requires a cooling which cannot be effected 
without ice or a refrigerating machine. Every creamery and 
dairy not provided with a machine should, therefore, have an ice 
house, and a refrigerator or cooling room should always be con- 

Refrigeration is absolutely necessary to the proper manu- 
facture of butter, and is likewise necessary to the proper keeping 
or preserving of same after it is made. Refrigeration is applied 
in the manufacture of butter to the manipulation and proper 
tempering of the raw materials and the keeping of the butter 
when made at a low temperature to prevent deterioration. Con- 
sidering the great importance of refrigeration as applied to 
creamery products, comparatively little attention has been given 
to this branch of the business. It is not meant bv this that those 


who are operating creameries have not given careful thought to 
this matter, but that the refrigerating engineers and the makers 
of refrigerating machinery have not studied its application to 
creamery and dairy service as fully as they might. 

As in all other" branches of the refrigeration of perishable 
food products, the United States is in advance of other countries 
in the preservation, by cold, of milk, butter and cheese. Until 
a comparatively recent day, however, the most progressive of the 
dairy companies often cooled their cans of milk by immersing 
them in a bath of cracked ice. This process was not only cumber- 
some, in that it necessitated the repeated handling of the heavy 
cans, but the cans themselves were thus injured. The ice and 
water were scattered over the premises, which rendered cleanli- 
ness very difficult. A dairy establishment refrigerated artificially 
presents a neater appearance. The milk as it is brought in from 
the country is first tested for quality. It is then placed in a large 
tank, from which it passes through three sets of fine strainers, 
which remove all small particles of dirt or dust that may have 
gotten into the cans. It then passes through a series of pipes, 
which are submerged in a large brine tank. The tank contains 
the ammonia expansion coils, by which the brine is kept at the re- 
quired temperature. After passing through these coils the milk 
is drawn off into cans, which, in turn, are stored in a large re- 
frigerator, kept at a temperature of about 35°. 

Denmark and Sweden in Europe have made the greatest ad- 
vance in the refrigeration of the products of the dairy, ma- 
chinery being extensively employed for that purpose. The cream- 
eries and butter factories of Belgium and Holland are also be- 
coming more modern in this respect year by year. A late inno- 
vation in the dairy industry in northern Germany and Denmark 
is the process of freezing milk into blocks, and shipping it abroad 
as milk ice, mostly to England. The required machinery agitates 
the milk during the freezing process, so that when ready for 
the market the substance of the frozen milk is uniform through- 

The pasteurization of the milk, which is now becoming quite 
general in the larger creameries in this country, as it is in Euro- 
pean countries, notably Denmark and Belgium, calls for addi- 
tional demands on refrigerating apparatus, as it is found essen- 


tial to reduce the temperature after pasteurization as rapidly as 


There is at the present time considerable controversy be- 
tween those who advocate the use of ice for creamery or dairy 
refrigeration and those who recommend refrigerating machinery. 
There should be no quarrel between these two different methods, 
as each one has its proper sphere, and there are cases where the 
selection of either one or the other would be a matter largely of 
individual opinion. Where natural ice can be stored cheaply at, 
say, a cost of $i.oo a ton or less, and where the quantity of milk 
to be handled would not exceed 10,000 or 15,000 pounds per day, 
the use of natural ice is usually to be preferred to installing re- 
frigerating machinery. On the other hand, where the quantity 
of milk to be handled is large and ice comparatively expensive, a 
refrigerating machine can profitably be employed. 

The advantages and disadvantages of the mechanical sys- 
tems over ice have recently been quite fully investigated by Prof. 
Oscar Erf, late of the College of Agriculture, University of Illi- 
nois. His deductions, however, were based on conditions which 
do not apply in states of about the same latitude as New York, 
Michigan, Wisconsin and Minnesota, and even south of these 
latitudes there are places where natural ice can be housed at much 
less cost than 90c. per ton, which he has taken as a basis. His 
investigation seems to have been conducted from an intelligent 
and fair minded standpoint, and his results are useful to creamery 
men, if proper allowances are made for the difference in latitude 
and other working conditions. Prof. Erf gives his results in de- 
tail, but we will only consider his summary of the disadvantages 
of mechanical refrigeration, as follows:* 

I.— Large capital invested. 

2. — Necessitates daily or continual operation, unless provided with 
large storage tanks. 

3. — Operating expenses for labor, coal, oil, ammonia and repairs. 

4. — Excessive dryness in such refrigerators, often causing a great 
shrinkage in the products. 

5. — Great risks for accidents that might happen, such as breakage 
on machine? and the delay of repairs. 

6. — Expense of pumping water for condensing ammonia. 

♦From Ice and Rirfrigeration, June, 1902. 


The advantages offsetting these disadvantages by using machinery 
for refrigeration, as compared with the use of natural ice: 

I. — No risks to nm in securing cold whenever needed. 

2. — Practically no variation in cost of producing cold from year to 

3. — The refrigerator is under better control. 

4- — Any temperature may be practically obtained above zero. 

5. — Atmosphere is dryer in refrigerator; hence butter is less' suscepti- 
ble to mold. 

6. — Less" disagreeable labor, such as the handling of ice. 

7. — Cold room can be kept cleaner. 

8. — Does away with the impurities imbedded in river and pond ice. 

9.— Provides for a more perfect method of cream ripening, which 
results in a better product. 

10. — Secures economy of space in the cool room, which lessens the 
radiating surface for same amount of refrigeration. 

The disadvantages as set forth are sufficiently plain to all 
who have had experience with refrigerating machinery. The 
advantages which are cited are more or less true, especially as 
applied to the ordinary appHcation of ice as generally used in 
creameries. Should the gravity brine system be used, as de- 
scribed further on, there would be : 

I. — Absolutely no risk to run in securing cold whenever needed. 

2. — Any temperature may be practically obtained down to 15° F. 

3. — The refrigeration would be under fully as good control and a more 

uniform temperature could be obtained than by the use of re- 
frigerating machinery. 
4- — The moisture in the atmosphere of the cold room could be carried 

at any temperature desired and under as good control as with the 

mechanical system. 
5. — The amount of disagreeable labor required, should an ice crusher 

and ice elevator be used, would be very small indeed. 
6. — The cold room can be kept as clean as with any system. 
7. — Impurities in the ice would have no influence on the air of the room 

for the reason that the air does not come in contact with the ice. 
8. — As perfect results can be had in the ripening of cream. 
9. — The economy of space in the cold room would be as g^reat as with any 


In other words, the gravity brine system will produce any 
results which can be had with refrigerating machinery down 
to a temperature of 15'' F., and besides this it is absolutely sure 
against a break-down. 


A cooling room for maintaining the butter at a low tem- 
perature after being made, is admitted to be absolutely necessary 
in every creamery, and it cannot be dispensed with, except in 
cases where butter is loaded into a refrigerator car each day. 



Even then the butter will handle much better and arrive on the 
market in much better condition if it is hardened so that it will 
carry without shaking or slopping in the tub, to say nothing of 
the advantages of always having it at a low temperature until 
consumed. Butter is practically at its best when first made, and 
the nearer it can be retained in this condition until consumed, 
the better satisfaction it will give the customer and the greater 


<SFMCE OQerrvELM D(l jrvixa fil VLCo with MjrtA\/irt<Ls|] 



will be the ultimate gain to the creamery man. When butter is to 
be shipped frequently, a small cooling room, constructed with ice 
chambers above the storage room, essentially as outlined in Figs. 
I and 2, should be built in every creamery not provided with me- 
chanical refrigeration. It is much better to place the ice over the 
room than it is to put the ice in a rack at one end or one side of 
the room. A lower temperature will be obtained and a dryer 
atmosphere will result, owing to the circulation of air, as indi- 
cated by the arrows. A room of this kind should be well 




built, and a few dollars extra spent in the insulation of same 
will be saved in a short time in the saving in the quantity of 


i - 



ice required. The temperature to be obtained in the room 
also depends on good insulation. If the insulation is thor- 
ough, a temperature of 36° to 40° F. may be depended upon. 


Of course, at the time when warm butter is placed in the room, 
the temperature will naturally rise to quite an extent. The con- 
struction of a room of this kind can be adapted to suit local con- 
ditions and the nature of the materials which can be most readily 
obtained. The detailed description which follows, of a room con- 
structed on the plan as laid down in the preceding paragraphs, 
will be of considerable value and interest to owners of creameries. 
The floor joists, ceiling joists and side wall studding should 
all be filled with mill shavings, sawdust, tan bark, cut straw or 
any similar material. This material, however, must be dry and 
protected on the outside and inside by the best grades of insulat- 
ing paper (not the ordinary rosin sized or common building 
papers). Care should be taken that in all corners the paper is 
thoroughly lapped to make an absolutely air tight surface, so as 
to prevent a circulation of outside air into the space which is 
filled with the insulating or packing material. It is best to 
double-board the outside of the room and put the insulating paper 
between. On the inside of the studding and on the top of the 
floor joists and on the bottom of the ceiling joists use matched 
boarding. Covering this interior surface should be placed a 
much better grade of insulating material than the filling between 
studs and joists. This may be of hair felt, sheet cork, 
granulated cork, rock fiber • felt, mineral wool, Cabot 
quilt, or any of the best grades of insulating materials. If 
there is any liability of trouble from rats or mice, they can be 
kept out of a room of this kind by using an inch or two of 
rock fiber felt or mineral wool on the outside of all walls. 
Rats or mice cannot work in either of these materials. The rock 
fiber felt spoken of is practically a mineral wool made up in the 
form of sheets or boards. The materials indicated may be used 
to a thickness of 2, 3 or 4 inches, depending upon the amount of 
money the owner is willing to spend and cost of refrigeration. 
These various materials must of course be put on between bat- 
tens or cleats of sufficient thickness to flush up even with the lay- 
ers of insulating material. If hair felt, sheet cork or rock fiber 
felt is used, the different thicknesses should be separated by a 
good grade of insulating paper. The interior of the room should 
be lined with matched stuff, preferably of poplar, spruce or hem- 
lock. (The chapter on "Insulation" may be of interest in this 


connection.) If it is desired to wash out a refrigerating or 
cooling room of this kind from time to time, the interior finish 
may be of shellac or hard oil, preferably shellac, or, the. inside 
surface may be coated with whitewash, which may be renewed 
from time to time. (See chapter on "Keeping Cold Stores 
Clean.") The joists for supporting the ice should be of fairly 
strong material, depending on the size of the room and should 
be pitched slightly toward the drain end of the ice floor. The 
joists for supporting the ice are not carried into the insulation, 
but rest on ribbands of 2x4s spiked onto the outside of the 
insulation. A batten should be set in the insulation for receiving 
these ribbands. The pan or floor under the ice consists simply of 
two thicknesses of dressed and matched stuff with a covering or 
lining of No. 20 galvanized iron. A loose rack of wood should 
be placed on this iron floor to prevent its wearing or getting 
punctured in handling the ice thereon. The galvanized iron 
should be turned up on the sides 4 to 6 inches. The circulation 
of air is provided for by placing a tight board screen on one side 
of the ice spat^e which is carried up to near the ceiling. The 
other or opposite side of the ice space has cleats or slats which 
keep the ice in place and allow a circulation of air. This screen 
and the slats mentioned are of course fastened to 2x4s or to 
2x6s, which form the open spaces for the circulation of air on 
the two sides of the ice chamber. The screen and cleats should 
be beveled on the top and bottom so that any dripping will be on 
the galvanized iron pan and not into the air flues and then down 
into the room. These various parts are illustrated in Fig. 2, but 
are not shown in detail. For filling ice into the ice chamber, a 
door may be provided at any point, but should not be on the side 
where the air flows down from the ice room to the storage room 
or up from the storage room into the ice chamber. This ice door 
may be at the top, and the room can be filled from the floor above 
if convenient. Both the ice door and the door for entering the 
room are preferably one of the special dix^rs which are on the 
market and which cost but ver>- little more than the home-made 
door, and are superior in every way. 

The above cooling room is intended to be filled from an in- 
dependent ice house, which should be located as near the cooling 
rtvni as converienl. 



The following description,* by W. G. Newton, will be of 
interest : 

The ice house is in the opposite end of the building from the boiler 
room and the ice is put right in on the ground floor and the refrigerator 
is built next to it and holes cut through next to the floor for the cold 
air to enter and same at top for warm air to go out. The ceiling over 
the ice needs to be from four to six feet higher than it is in the refrig- 
erator, then if the outlets for the warm air are right up close to the 
ceiling (not having so much as a piece of molding between the top of 
the hole in the side and the ceiling overhead), the dampness will all go 
off with the warm air up over the ice, leaving your refrigerator dry and 

As to the expense of building, it is not much, as a room 20x20 or 20x30 
feet at most will hold ice enough to cool most of the creamery refrigerators 
if they have some ice stored elsewhere for other uses. All that is neces- 
sary is to have the walls of the ice house properly insulated with sawdust 
and air spaces and then the yearly renewal of sawdust in which to pack 
the ice is saved. 

Not only creameries but several large meat markets here have this 
kind of an ice house and refrigerator combined and they are giving the 
best of satisfaction. There is a patent on them. The days of building 
refrigerators with ice overhead have gone by in this section of the country. 

This appears like a fine arrangement to save labor and pro- 
duce the lowest possible temperature with ice. The ice room 
must be as well finished and insulated as the refrigerator and 
no sawdust or packing material used on the ice. It would be 
advisable to build the ice room more than four to six feet higher 
than the refrigerator, and ten or fifteen feet would be better. 
An ice room of say 20x30x20 feet dimensions should be suf- 
ficient for an ordinary creamery, but this depends on what is to 
be done with the milk. The storage of ice in a building, as is 
well known, tends to cause it to decay and deteriorate rapidly, 
and this is the only real objection to the plan, as the ice room 
would be in bad condition long before the refrigerator. A well- 
built house on a stone or brick foundation would be almost a 
necessity for the purpose. 

In practice, in some extreme cases, it has been found advisa- 
ble to fill into the ice house as many pounds of ice as there are 
pounds of milk to be treated, or to harvest 100 cubic feet of ice 
for each cow furnishing milk to the dairy or creamery. Less 
than one-half this quantity may be ample in many cases, so much 
depends on the treatment to which the milk and manufactured 

♦From A'rtv York Produce Review. 


product is subjected. Where pasteurizing is practiced, much 
more ice is required, especially where no well water is available. 
During the winter ice or snow may be used which is simply 
hauled together in a heap near the creamery, so that no ice is 
taken from the ice house until April or May. 

Where separators are used, no ice is needed for raising the 
cream, but the latter needs cooling either as it runs from the 
separator or after the ripening, before churning. 

Ice is also needed in the hot summer months to cool the 
butter before or between the workings, and for keeping it firm 
in texture before it is shipped, so that it may leave in the very 
best condition for standing exposure to heat while in transit to its 
destination. Butter in prints is sometimes shipped in cases with 
an ice box filled with crushed ice in the center. 

The amount of ice required for these various purposes 
varies according to local conditions, and cannot be definitely 
stated, though it may be calculated approximately. The chapters 
on "Harvesting, Handling and Storing Ice" and "Ice Houses" 
give methods of handling ice and details for construction of ice 
houses of various capacities. 


In the transportation of milk and cream, baggage cars, re- 
frigerator cars, and cars especially constructed for the purpose 
are employed. The railroads adopt the style of car best suited 
to their individual requirements. In the case of light shipments 
and short hauls, superannuated baggage cars appear to meet every 
requirement and are generally moved in conjunction with local 
passenger trains. In the case of long hauls, however, refriger- 
ator or special milk cars are used. These cars are plentifully 
supplied with ice during the warm summer months and, in ex- 
tremely cold weather, are often steam-heated to prevent the milk 
from freezing. Cleaning generally takes place after each run, 
the cars being either swept or washed by means of a hose. 
Trains making long hauls are usually composed entirely of 
refrigerator or special milk cars and are operated on about pas- 
senger schedule time, the actual running time being as fast as 
fifty miles an hour. The capacity of a large milk car is 325 
ten-gallon cans. 


Nearly all railroads which handle a large milk traffic have 
well-built covered receiving and shipping stations along their 
lines, nearly all of them with an ice house connected in which 
natural ice in sufficient quantity is stored during the winter. 

Shipping stations are equipped with large cooling vats in 
which cans of milk are placed immediately after being delivered 
by the farmers. These vats are filled with water and ice, the 
milk is stirred and cooled down to 40** F. within forty minutes 
from the time it is received, and kept in ice water until the train 
arrives, when it is loaded direct from the vats into a refriger- 
ator car. 


The application of the Cooper gravity brine system to the 
refrigeration of a creamery cooling room and freezing room is 
shown in Figs. 3 and 4. They also show the arrangement of 
ice crushing and ice handling apparatus, which will deliver 
crushed ice to any convenient point in the creamery workroom 
for the cooling of cream, butter, shipping, or other purposes. 
Fig. 3 shows the plan view of one end of the creamery with 
ice house adjoining. The refrigerated space in the creamery 
consists of a cooling room with a capacity of about one carload. 
The butter freezing room has a somewhat larger capacity. The 
relative size of these rooms can, of course, be changed to suit 
any conditions. The cooling room and freezing room are both 
entered from the vestibule and not from the workroom. This 
prevents the access of warm air into the rooms, which is very 
important, especially in the freezing room. If it is desired, the 
cream cooling vats may be placed in a cooling room of this kind, 
but as planned, it is intended that the cream should be cooled 
with crushed ice or cold well water. There are a number of 
different ideas on arrangements of this kind, but with the ap- 
paratus shown any arrangement can be provided to suit the ideas 
of the owner or local requirements. 

The gravity brine system, patented by the author, which 
refrigerates the cooling room and freezing room, may need a 
few words of explanation. Referring to the section (Fig. 4) 
it will be seen that the gravity brine system consists of a series 
of pipe coils and connections. In this case there are two coils 





in the tank for the cooling room and two coils in the tank for 
the freezing room. These coils are connected to similar coils 
of larger size which are located in the cooling room and freezing 
room. It will be noted that the coils in the tank are connected 
at their lowest extremity to the lowest point of the coils in the 
room, and that the coils in the room are connected at their highest 
point to the highest point of the coils in the tank. This estab- 
lishes means for a complete circulation of brine with which the 
coils are filled. The coils in the tank are filled around and be- 
tween with crushed ice and a small quantity of salt. This cools 
the brine in the coils in the tank, and by reason of its being 
heavier, the brine flows down into the coils in the room. It is 
here warmed by contact with the air of the rooms and flows 
upward to the highest point of the coils in the tank. A very 
slight difference in temperature will cause a circulation. The 
advantages of this system over direct icing, as shown in Fig. i, 
are that the temperature can be controlled as desired, and the 
rooms being cooled by pipe surfaces, the humidity of the room 
may be maintained at a proper point. In the freezing room a 
temperature as low as 15** F. is comparatively easy to obtain, 
and a temperature as low as 10** or 12° may be had by crowding 
the apparatus and using an increased quantity of salt. The 
gravity brine system is automatic in its action, requiring no 
power to produce circulation, and any results may be obtained 
which can be produced by refrigerating machinery, limited only 
by the temperature which can be produced. If it is desired to 
convey cold brine through pipes for use in cooling cream or 
pasteurizing, the brine may be pumped to any point desired in 
the creamery. 


The ice crusher and ice elevator which are clearly shown 
in Fig. 4 are quite simple in their operation, and as labor saving 
machines are the best form of apparatus which has been applied 
to the handling of ice. It only requires that the ice be broken 
into irregular pieces of 20 to 30 pounds or thereabouts, and 
fed into the ice crusher. The crusher breaks the ice into small 
pieces the size of hen's eggs or smaller, and it drops into the 
bucket elevator where it is raised to a point sufficiently high to 




allow its being spouted to a convenient point in the creamery 
and to the flexible spout which is used to feed ice into the tanks 
containing primary coils of the gravity brine system. Four or 
five tons of ice may be handled with an apparatus of this kind in 
half an hour. As recommended in connection with the "Model 
Creamery Ice House" described in the chapter on **Ice Houses," 
the ice should not be covered with sawdust or packing material 
of any kind, and where the ice is clean in the ice house, the 
labor of handling same to the crusher and delivering to any con- 
venient point in the creamery is very little as compared with 
the old-fashioned method. This outfit and apparatus is not rec- 
ommended for the average small creamery, but where several tons 
of ice are to be handled each day, or where it is desired to store 
a certain portion of the product of the creamery and carry it for 
several months, as good results may be obtained with the gravity 
brine system as with a refrigerating machine. The expense of 
installing, while it is considerably more than any of the old style 
refrigerators, is less than for a good refrigerating machine. 


The following is a portion of an address by Loudon M. 
Douglas, read before the Cold Storage and Ice Association at 
Islington, England: 

The main object in view in cooling fresh milk for immediate con- 
sumption is to arrest the development of the spores which produce bac- 
teria, and which, in their turn, destroy the milk— that is to say, the milk 
becomes sour. It will be understood, however, that the bacteria referred 
to are those which are always found in the milk produced, even under 
proper hygienic conditions. Heat is the essential condition for their 
development, and, in the absence of that condition, they will remain in- 
active. Of pathogenic bacteria we need not speak here. 

Properly speaking, under good hygienic conditions, it should only be 
necessary to cool the milk before sending it out, and this is practiced 
by some retailers. It may, however, be considered an advantage to pre- 
viously pasteurize the milk at a high temperature, and then cool it down. 
It is not easy to say which way is the better. In any case both methods 
are in use. 

In cooling town's milk direct from a temperature of, say, 68** to 38** 
F., all that is necessar\' is a small refrigerating machine connected to a 
circular cooler. The cold brine from the machine is circulated through 
the flutingf* of the cooler and the milk run over. When it reaches the 
bottom and escapes', the temperature will be about 38° R, the balance of 
the heat units having been absorbed by the brine. But by means of a 
similar small machine a very large cooling effect may be produced by 

•Extracted from Ice and Refrigeration, June, 1904. 


having a large insulated store tank fitted with agitating gear and filled 
with either water or non-freezable brine 

It is* obvious that, by working the small machine for a lengthened 
number of hours upon this* store, the heat will be extracted and a large 
volume of a very cold medium will be available. This can be utilized 
to cool in turn a very large quantity of milk in a short time, a quantity 
quite beyond the power of a small machine to deal with directly. Thus, 
by intelligent working a small machine costing a comparatively small 
sum can be made to perform a large amount of work. 

In the case where milk is previously pasteurized the procedure is 
different, and can not be better demonstrated than by referring to a 
large dairy where the work is carried out. The dairy in question handles 
1,000 gallons* of fresh milk per day, all of which is distributed either 
directly to consumers or to shops for such distribution, and, in consider- 
ing the question of refrigeration, it was stipulated that the cooling of 
the quantity named should be performed in one hour, and that there 
should also be provision made for cooling a chum store, a cream store, 
and a butter store of certain dimensions". Now, the machine necessary to 
cool the 1,000 gallons from 68° to 45** F. in one hour, equal to the 
elimination of 230,000 B.T.U., would be a very large one, whereas the 
B.T.U. to be eliminated from the accessory stores would be comparatively 
few. Obviously, therefore, if a large machine had been installed it would 
have been much of its time idle. The problem, therefore, was to find 
a machine which would perform the whole work during working hours. 
This was done by providing storage tanks for 1,000 gallons of brine, 
and the heat is" extracted from this during a series of hours. Obviously 
all this brine when cooled down is available, and it is only necessary to 
run it through a large capillary cooler while the milk to be cooled is run 
over the outside. The heat of the milk is transferred to the brine, and 
thus the cooling is accomplished with great rapidity. The pasteurized 
milk is first of all cooled with" ordinary water from the town's* supply 
to 68" F., and from that temperature is lowered through 23° to 45° F. 
The machine used is capable of eliminating 45,000 B.T.U.s per hour. 
But the total number of B.T.U.s to be eliminated are altogether 35SP^f 
taking into account the accessory work to be done; thus, if 355,000 is di- 
vided by the output of the machine, viz., 45,000, you get the number of 
hours* work necessary, viz , eight, or an ordinary working day. There 
is a margin of 5,000 B.T.U.s allowed for contingencies. 

The creamery system has now become well established through- 
out Europe, and feeding stations to main creameries are recognized as 
essential to economical working. The process which is usually carried 
out in these places is as follows: 

The milk is brought by the farmers to the creamery, sampled, weighed, 
pasteurized, and separated. When the cream leaves the separator it may 
be at a temperature of from 170° to 180° F., and is therefore immediately 
run over a circular capillary cooler, through which water is circulated, 
and reduced to about 65° F. It is then run over another cooler, through 
which brine is circulated and cooled to about 45° F., being caught in 
churns, and in this state taken to the main creamery to be ripened and 
made into butter. The separated milk is treated in very much the same 
way. A large surface water cooler reduces the temperature to 68° F., 
and the milk is" then run over a small cooler and reduced to 48° F., at 
which temperature it is returned to the farmer. 

Some actual tests of a machine (at Ballinorig) might be appropri- 
ately recorded here: 

I. — 100 gallons of brine were cooled from 40° F. to 27° F. in one 
hour (condensing water 57° F.), or equal to the elimination of 13,000 
B.T.U. per hour. 


2. — 100 gallons of brine were cooled from 27° F. to 17° F. in one 
hour (cooling water, 58° F.) =10,000 B. T. U. per hour. 

3.— 100 gallons of brine were cooled from 45° F. to 31° F. in one 
hour (cooling water, 57** F.) =14,000 B.T.U. per hour. 

These tests bring out very strongly the fact that at comparatively 
high temperatures cooling is' effected at a much more rapid rate than at 
the lower range of temperatures, and the amount of energy consumed is 
greater at lower or ice-making temperatures than at the higher, and this 
must be borne in mind in specifying the duty of the machine. The 
machine in question is one of the very smallest made, but the same 
result is obtained with machines of all sizes. 

Perhaps the greatest interest is attached to the application of refrig- 
eration to a central or main creamery, for in such a place all the im- 
portant applications can be put into effect. These may be classified thus: 
A, cooling cream from separator; B, cooling separated milk; C, cooling 
ripened cream; D, cooling water for washing butter; E, cooling a butter 

As in the auxiliary creamery, the cream is first of all cooled with water 
to about 68** F., so in the main dairy. The cream is brought down to 
a temperature of 48° F. by passing it over a circular capillary cooler, and 
is then run into the ripening vats. Here the process of ripening rapidly 
increases the temperature again, and in about eighteen or twenty hours 
it is at about 65** F. At such a temperature it would be ruinous to chum, 
inasmuch as the texture of the butter would be oily and bad, and there 
would also be an excessive loss of butter fat in the buttermilk. The per- 
fect churning temperature (in summer) may be anything between 48** 
and 52° F., and to attain this it is obvious that the temperature of the 
cream must be lowered some 13° to 17° F. The most economical ar- 
rangement by which this can be accomplished is by having the cream- 
ripening vats sufficiently high up in the creamery to enable the cream to 
run over a capillary cooler, then flow into the churn. Such an arrange- 
ment is simple and works well. By proper and intelligent adjustment of 
the appliances, the cream can be reduced in temperature to 48** F. pre- 
cisely, if wanted. 

Separated milk in the main creamery is treated in the same way as 
in the auxiliary, viz., first of all passed over a large circular cooler, in 
which water takes up the heat from the milk. It is then passed over a 
small cooler in which brine is the cooling medium, and delivered to the 
farmer at 48° F. 

Cold water in a creamery is very desirable. The average temperature 
of well water in the British Isles is 52° F., but that is not considered to 
be low enough for washing purposes ; besides, if it were, well water 
is not always available. Hence, orovision has to be made for cooling 
water to a very low temperature. This is done in a separate tank, usually 
placed in a sufficiently elevated position to command the butter worker 
and churn. An insulated tank of, say, one to 500 gallons* capacity, is 
fixed on the wall with brackets, or on a platform, and in this is fixed 
a direct expansion or brine coil connected to the machine. The cooling 
is more quickly produced if a small agitator is placed in the tank, as by 
that means the water is more quickly brought in contact with the cooling 
surface. Water at from 45° to 58° F. seems to be generally preferred. 




Cold Storage is having an important influence in developing 
the apple industry as a stable business. Instead of an incidental 
feature of the general farm, the apple is now the principal crop 
in large sections of the country, and its production and the 
handling and marketing of the crop are becoming highly special- 
ized forms of agriculture and of trade. 

Formerly the marketing of the crop was largely controlled 
by the apple grower, but now the growing of the crop and its 
sale are rapidly differentiating into two distinct lines. In many 
of the principal fruit-growing districts the handling of the crop 
and its marketing are controlled largely by fruit organizations or 
by apple merchants who buy the fruit in the orchards and who, 
through the special development of fruit and market statistics, 
are better able than the fruit grower to regulate its distribution 
and sale. This greater stability and specialization in apple grow- 
ing is accompanied by a large amount of speculation. Through 
a combination of the buyers the fruit may not always sell in the 
orchard for its real value, but on the other hand the severe com- 
petition in buying in those sections where the industry is es- 
pecially well developed frequently brings the grower the highest 

Apple storage is not always profitable. It is an insurance 
against the premature deterioration of the fruit, but when the 
picking season is unusually hot and there are delays in getting 
the fruit into storage, the subsequent losses are sometimes very 
heavy. On the other hand the autumn may be unusually cool 

♦Extracts from Bulletin No. 48, Bureau of Plant Industry. United States Depart- 
ment of Ai;riculture, by G. Harold Powell, Assistant Pomolosist in charge of Field 
Investigations, and S. H. Fulton. Assistant in Pomology. 


and favorable for storing large quantities of apples in common 
storage. As a result the markets are well supplied with this 
fruit through the winter, causing the cold storage stock to be 
held back till late in the season, when it has to be rushed on the 
market and sold at a sacrifice on account of the approaching 
warm weather and the free use of southern early fruits. 

On the whole the development of the cold storage business is 
proving beneficial to the apple industry in encouraging the de- 
velopment of apple growing over large territories, in making the 
investment of capital in it safer, in developing it as a highly 
specialized type of agriculture and trade, and in making a val- 
uable food product available to an increasing number of people 
over a greater part of the year. 


There is a good deal of misapprehension as to the function 
of the cold storage house in the preservation of fruits. This 
condition leads to frequent misunderstandings between the ware- 
houseman and the fruit storer, though they might be avoided and 
the condition of the fruit storage business improved if there was 
a clearer definition of the influence on fruit preservation of cul- 
tural conditions, of the commercial methods of handling, and of 
the methods of storage. 

A fruit is a living organism in which the life processes go 
forward more slowly in low temperatures, but do not cease even 
in the lowest temperatures in which the fruit may be safely 
stored. When the fruit naturally reaches the end of its life it 
dies from old age. It may be killed prematurely by rots, usually 
caused by fungi which lodge on the fruit before it is packed, 
and sometimes afterwards. The cold, storage house is designed 
to arrest the ripening processes in a temperature that will not 
injure the fruit in other respects and thereby to prolong its life 
history. It is designed also to retard the development of the 
diseases with which the fruit is afflicted, but it cannot prevent the 
slow growth of some of them. It follows that the behavior of 
different apples or lots of apples in a storage room is largely de- 
pendent on their condition when they enter the room. If they 
are in a dissimilar condition of ripeness, or have been grown or 
handled diflferently, or vary in other respects, these differences 


may be expected to appear as the fruit ripens slowly in the low 
temperature. If the fruit is already overripe, the low tempera- 
ture cannot prevent its deterioration sooner than would be the 
case with apples of the same variety that were in a less mature 
condition. If the fruit has been bruised, or is covered with rot 
spores, the low temperature may retard but can not prevent its 
premature decay. If there are inherent differences in the apples 
due to the character of the soil, the altitude, and to incidental 
features of orchard management, or variations due to the meth- 
ods of picking, packing, and shipping, the low temperature must 
not be expected to obliterate them, but rather to retard while not 
preventing their normal development. 

In general it is the function of the cold storage warehouse 
to furnish a uniform temperature of the desired degree of cold 
through its compartments during the storage season. [The ex- 
periments so far conducted cover only the influence of tempera- 
ture in cold storage. Much has yet to be done in determining 
the best methods of refrigerating which control air circulation, 
ventilation and humidity. More is promised along these lines.] 
The warehouse is expected to be managed in other respects so 
that the deterioration of the fruit or any other injury may not be 
reasonably attributed to a poorly constructed and installed plant, 
or to its negligent or improper management. The warehouseman 
does not insure the fruit against natural deterioration; he holds 
it in storage as a trustee, and in that relation is bound to use only 
that degree of care and diligence in the management of the ware- 
house that* a man of ordinary care and prudence would exercise 
under the circumstances in protecting the goods if they were his 
private property. 

If the temperature of the storage rooms fluctuates unduly 
from the point to be maintained and causes the fruit to freeze 
to its injury, or to ripen with abnormal rapidity, or if the man- 
agement of the rooms or the handling of the fruit in other re- 
spects can be shown to have been faulty or negligent, the ware- 
house has failed to perform its proper function. 


An outline of the apple storage experiments of the United 
States Department of Agriculture is presented here. The fol- 


lowing problems were under investigation during two apple 
seasons : 

I. — A comparative test of the keeping quality of a large 
number of varieties grown in different regions and of the same 
varieties grown under different conditions and in different lo- 

The fruit was stored in closed 50-pound boxes in a tempera- 
ture of 31** to 32° F. One-half of the fruit in each box was 
wrapped in paper. 

2. — A determination of the influence of various commercial 
methods of apple handling on the keeping quality of the most im- 
portant varieties in the leading apple-growing regions of the 
eastern United States. 

Each variety was picked at two different degrees of ma- 
turity: First, when nearly grown but only half to two-thirds 
colored, or about the time when apples are usually picked; sec- 
ond, when the fruit was fully grown and more highly colored, 
but still hard. In each picking the fruit was separated into two 
lots, representing the average of the lightest and of the darkest 
colored or most mature specimens. 

Part of the fruit of each series was sent to storage as soon 
as picked. A duplicate lot was held two weeks in the orchard 
or in a building, either in piles or protected in packages, before 
it was sent to storage. 

Comparative tests were made to determine the efficiency of 
different kinds of fruit wrappers on the keeping of the fruit, 
and observations on the behavior of the fruit in closed and ven- 
tilated packages were recorded. 

3. — A determination of the influence of various cultural and 
other conditions of growth on the keeping quality of the fruit. 

Comparison was made with the same variety from heavy 
clay and from sandy soils, from sod, and from cultivated land, 
from young, rapidly growing trees, and from older trees with 
more steady habits. 

4. — A determination of the behavior of the fruit under the 
conditions outlined in temperatures of 31° to 32° F., and in 34 "* 
to 36^ F. 

5. — A determination of the behavior of the fruit when re- 
moved from storage, and of its value to the consumer. 


The fruit used in the investigations was taken from central 
and eastern Kansas, southwestern and central Missouri, southern 
and central Illinois, western Michigan, northeastern West \'ir- 
ginia, northern and western Virginia, western North Carolina, 
central Delaware, southern Maine, central Massachusetts, and 
from eastern, central, and western New York. A description of 
each orchard accompanies the data included in the account of the 
variety test. 

It was necessary to duplicate the work in different parts of 
the country, as the climatic and other conditions and the varieties 
differ in each section. The work must be repeated for several 
successive seasons before general conclusions can safely be drawn 
from it, as the climatic conditions differ each year and thereby 
affect the results. 


In recent years there has been a tendency to pick the apple 
crop relatively earlier in the season than formerly. It is quite 
generally supposed that the longest keeping apples are not fully 
developed in size or maturity and that the most highly colored 
fruit is less able to endure the abuses that arise in picking, pack- 
ing, and shipping. 

Aside from these general impressions, several important 
economic factors have influenced the picking time. A large 
proportion of the apple crop is purchased in the orchard by the 
barrel or by the entire orchard by a comparatively few apple mer- 
chants. The fruit may be picked and barreled either by the 
grower or by the purchaser, but with the growing scarcity of 
farm hands and other labor it has become necessary to begin 
picking relatively earlier in the autumn to secure the crop before 
the fall storms or winter months set in. 

The general increase in freight traffic during the past few 
years has overtaxed the carrying capacity of the railroads as 
well as their terminal facilities for freight handling, and has in- 
fluenced the apple dealers to extend the picking and shipping 
season over the longest possible time, in order to avoid con- 
gestion ami consequent delays in shipping and in unloading the 
fruit. The facilities at the warehouses are often inadequate for 
the quick handling of the fruit from the cars when it is received 


in unusually large quantities, and this condition has also favored 
a longer shipping season. 

In localities where the entire crop is sometimes ruined by 
the bitter rot after the fruit is half grown the picking of the 
apples is often begun early in the season in order to secure the 
largest amount of perfect fruit. 

It is not generally the case, however, that the immature and 
partly colored fruit has the best keeping quality. On the other 
hand, an apple that is not overgrown and which has attained 
full growth and high color, like the lower specimen of York 
Imperial in Fig. i, but is still hard and firm when picked, equals 
the less mature fruit (upper specimen, Fig. i) in keeping qual- 
ity, and often surpasses it. The mature fruit is superior in flavor 
aiid texture ; it is more attractive to the purchaser, and therefore 
of greater money value. It retains its plumpness longer and is 
less subject to apple scald. If, however, the fruit is not picked 
until overripe, it is already near the end of its life history, and 
will deteriorate rapidly unless stored .soon after picking in a low 

In the experiments with the Tompkins King and. the Sutton 
apples grown in New York on rapidly growing young trees pro- 
ducing unusually large apples, the fruit that was three-fourths 
colored kept longer than the fully colored apples from the same 
trees. Dark red Tompkins King showed 28 per cent of physio- 
logical decay in February following the storage. Light, half red 
Tompkins King from the same trees, picked at the same time, 
showed 10 per cent of physiological decay in February following 
the storage. Fig. 2 shows Tompkins King in February at two 
degrees of maturity in September, 1902, from young, rapidly 
growing trees. The upper specimen represents fruit that was 
highly colored but firm when picked: the lower specimen shows 
fruit one-half to two-thirds colored. The less mature fruit kept 
in good condition a month longer than the highly colored apple. 
These apples were overgrown — a condition likely to occur on 
young trees. Whether the same conditions hold true of other 
varieties that are overgrown has not been determined. 

From older trees, apples that are fully grown, highly col- 
ored, and firm when picked have kept as well in all cases (and 





better in many, as shown in Fig. i) than immature and under- 
colored fruit. 

A considerable number of later varieties may be picked when 
they are beginning to mellow, and will keep for months in prime 
condition provided they are handled with great care and quickly 
stored after picking in a temperature of 31° to 32° F. Fruit 
in this ripe state can not be left in the orchard or in warm freight 
cars, or in any other condition that will cause it to ripen after 
picking, without seriously injuring its value. In this ripe con- 
dition it should be stored in boxes, and a fruit wrapper will still 
further protect it. 

Apples that are to be stored in a local cold storage house 
to be distributed to the large markets in cooler weather may be 
picked much later than fruit requiring ten days or more in 
transit, but the use of the refrigerator car makes late picking 
possible where the fruit must be in transit for a considerable time 
in warm weather in reaching a distant storage house. 

While it is not the purpose of this publication to discuss 
cultural practices in the orchard, some suggestions in relation to 
the methods of securing more mature and more highly colored 
fruit may not be without value to the fruit grower. 

A large proportion of the poorly colored fruit from old or- 
chards is caused by dense-headed trees and close planting, which 
prevent the free access of air and sunlight and delay the maturity 
of the fruit in the fali. The fundamental corrective in such cases 
Hes in judicious pruning, by which means the fruit may be ex- 
posed to the sunlight. 

In other cases the poor color may be due to a combination 
of heavy soil, tillage, frequent turning in of nitrogenous cover- 
crops, spraying, and neglect in pruning. These conditions stim- 
ulate the trees to active growth, the foliage increases in health, 
size, and quantity, and, as the water-holding capacity of the soil 
is enlarged by the incorporation of the cover-crops and is re- 
tained by the tillage, the trees grow late in the fall and the fruit 
does not properly color before the picking season arrives. It is 
often possible to overcome the difficulty by severely pruning the 
top to let in more air and light. If this treatment does not prove 
efficient, the cover-crops may be withheld, when the fruit will 
usually mature earlier in the fall, unless the season is wet. As 





an additional treatment where necessary, the growth of the or- 
chard may be still further checked by seeding it down until the 
desired condition is attained. 

It is not possible to secure a. uniform degree of maturity 
and size when all the apples on a tree are picked at one time, as 
fruit in different stages of growth is mixed together on the same 
tree. The apples differ in size and maturity in relation to their 
position, the upper outer branches producing the large, highly 
colored and early ripening fruit, while the apples on the side 
branches and the shaded interior branches ripen later. Greater 
uniformity in these respects is approached by proper pruning 
and by other cultural methods, but the greatest uniformity can 
be attained when, like the peach or the pear, the apple tree is 
picked over several times, taking the fruit in each picking that 
approaches the desired standard of size and maturity. 

Summer apples, like the Yellow Transparent, Astrachan, 
and Williams, are usually picked in this manner, and fall varie- 
ties, like Twenty Ounce, Oldenburg, and Wealthy, are sometimes 
treated similarly. In recent years a few growers of winter ap- 
ples have adopted the plan for the late varieties, with the result 
that the size, color, and ripeness of a larger proportion of the 
fruit are more uniform. This method of picking is not usually 
adapted to the apple merchant who buys the crop of a large num- 
ber of orchards, and who can not always secure efficient or abun- 
dant labor, but for the specialist who is working for the finest 
trade and who has a storage house near by or a convenient re- 
frigerator car service to a distant storage house, the plan has 
much to commend it. 


The removal of an apple from the tree hastens its ripening. 
As soon as the growth is stopped by picking, the fruit matures 
more rapidly than it does when growing on the tree and matur- 
ing at the same time. The rapidity of ripening increases as the 
temperature rises, and it is checked by a low temperature. It 
appears to vary with the degree of maturity at which the fruit 
is picked, the less mature apples seeming to reach the end of 
their life as quickly as or even sooner than the more mature 
fruit. It varies with the conditions of growth, the abnormally 


large fruit from young trees or fruit which has been overgrown 
from other causes ripening and deteriorating very rapidly. It 
differs with the nature of the variety, those sorts with a short 
life history, like the summer and fall varieties, or like the early 
winter apples, such as Rhode Island Greening, Yellow Bellflower, 
or Grimes Golden, progressing more rapidly than the long-keep- 
ing varieties like Roxbury, Swaar, or Baldwin. 

Any condition in the management of the fruit that causes 
it to ripen after it is picked brings it just so much nearer the 
end of its life, whether it is stored in common storage or in cold 
storage, while treatment that checks the ripening to the greatest 
possible degree prolongs it. 

The keeping quality of a great deal of fruit is seriously in- 
jured by delays between the orchard and the storage house. This 
is especially true in hot weather and in fruit that comes from 
sections where the autumn months are usually hot. If the apples 
are exposed to the sun in piles in the orchard, or are kept in 
closed buildings where the hot, humid air can not easily be fe- 
moved from the pile; if transportation is delayed because cars 
for shipment can not be secured promptly, or if the fruit is de- 
tained in transit or at the terminal point in tight cars which 
soon become charged with hot, moist air, the ripening progresses 
rapidly and the apples may already be near the point of deter- 
ioration or may even have commenced to deteriorate from scald, 
or mellowness, or decay when the storage house is reached. 

On the contrary, the weather may be cool during a similar 
period of delay and no serious injury result to the keeping qual- 
ity, or the ripening may be checked in hot weather by shipping 
the fruit in refrigerator cars to a distant storage house. 

The fungous diseases of the fruit, such as the apple scab 
(Fusicladium dendriticum (Wallr.) Fckl.) and the pink mold 
(Cephalothecium roseum Cda.) which grows upon the scab, the 
blue mold (Penicillium glaiuum Link) which causes the com- 
mon, soft, brown rot, the black rot (Sphceropsis malorum Pk.) 
and the bitter rot (Glceosporium fructigenum Berk.), develop very 
fast if the fruit becomes heated after picking. The conditions 
already enumerated which cause the fruit to ripen quickly during 
the delay between the orchard and the storage house are also 
most favorable to the development of fruit diseases. It is there- 


fore of the greatest importance that the fruit be stored imme- 
diately after picking, if the weather is warm, in order to insure it 
against the unusual development of the fungous rots. 

In the fall of 1901, when the weather in western New York 
was cool, there was no apparent injury from delaying the storage 
of a large number of varieties two weeks and then shipping the 
fruit to Buffalo, the transit occupying from one to three days. 
There was also no apparent injury to the fruit from Virginia 
treated in a similar manner, but in southwestern Missouri, where 
it was warmer, the apples delayed two weeks before storing were 
seriously injured in their commercial keeping qualities. 

The results accomplished during 1902 have been of the most 
instructive character. During the latter half of September the 
temperature in eastern New York averaged about 62° F., with 
a humidity of 84°. During the first half of October the average 
temperature was 53° F. and the humidity 80°. 

Rhode Island Greening, Tompkins King, and Sutton apples 
picked September 15, 1902, and stored within three days, were 
firm till the following March, with no rot or scald, but fruit from 
the same trees not stored till two weeks after picking was badly 
scalded or decayed by the ist of January. None of the imme- 
diate-stored fruit was scalded or decayed by the ist of February, 
but the delayed Sutton and Rhode Island Greening apples were 
soft and mealy, and one-third were scalded at that time, while 
nearly 40 per cent of the delayed Tompkins King were soft and 
worthless. The commercial value of these varieties was injured 
from 40 to 70 per cent by the delay in storage. 

Apples of these varieties picked from the same trees on Oc- 
tober 5, 1902, and stored immediately, and also some stored two 
weeks later, were less injured by the delay, as the temperature 
and humidity were not sufficiently high to cause rapid ripening 
or the development of the fruit rots. 

From the standpoint of the orchardist or apple dealer who 
can not secure quick transportation to the large storage centers, 
or who can not obtain refrigerator cars, or who is geographically 
situated where the weather is usually warm in apple-picking 
time, the local storage plant in which the fruit can be stored at 
once and distributed in cool weather offers important advantages. 
The importance of this phase of the fruit-storage business and its 


relation to the fruit-growing industry are emphasized as the 
apple business enlarges. 


The investigations indicate that the mpening processes are 
delayed more in a temperature of 31° to 32° F. than in 35** to 
36° F. The apple keeps longer in the lower temperature, it 
scalds less, the fruit rots and molds are retarded to a greater 
extent, while the quality, aroma, flavor, and other character- 
istics of the fruit are fully as good, and when removed from 
storage it remains in good condition for a longer period. 

The impression is quite general that fall varieties and the 
tender early winter sorts, like Fameuse, Wealthy, and Grimes, 
are injured in some way by the low temperature, but the investi- 
gations of the Department of Agriculture indicate that these 
varieties behave more satisfactorily in every respect when stored 
at 31° to 32° F. 

If the fruit is intended for storage for a short time only, 
and it is desired to have it ripen before removing it from the 
storage house, then a higher temperature may be desirable to 
hasten the maturity. 

The influence of the temperature on the ripening processes 
appears to depend on the condition of the fruit. Baldwin, Esopus 
Spitzenburg, Roxbury, Jonathan, Lady Sweet, and other long- 
keeping eastern-grown varieties have been held in prime com- 
mercial condition throughout the storage season in a temperature 
of 35® F., when carefully picked and handled and stored soon 
after picking; but when the fruit was carelessly handled or the 
storage was delayed in hot weather, then a temperature of 31** 
to 32° F. was required to retard the ripening. 

It might be safe to use a temperature of 34° to 35"* F. in a 
storage house located near the orchard, in which the fruit may 
be stored immediately after harvesting, but for general commer- 
cial apple handling, a temperature as low as 32° F. is needed to 
overcome the abuses that usually arise in picking, packing, and 

No definite investigations have been made by the Depart- 
ment of Agriculture as to the effect of temperatures lower than 
31° F. The exact freezing point of apples has not been deter- 
mined, but it is below this point. It may possibly vary with the 


composition or condition of the variety. Under the most favor- 
able conditions, apples are sometimes commercially stored at 30® 
F. without injury, but 31° F. should be considered a critical 
temperature below which it is unsafe to store this fruit, except 
in houses that are properly constructed and in which tlie tem- 
perature is maintained uniform in all parts of the rooms. [The 
author's personal experience is that a temperature of 30° F. is 
better than any degree above that, and 29° F. is practicable and 
advisable for long-period storing of the better keeping varieties. 
To safely store at 29° to 30° F. it is necessary that a thorough 
forced circulation of air be employed (see chapter on "Air Cir- 
culation"), and in cooling the fruit down to the final carrying 
temperature, the refrigeration must not be applied too suddenly. 
If, say, the fruit has a temperature of 60° or 70° F. when placed 
in storage, a period of two or three weeks should be consumed 
in reducing to 29° or 30° F. This applies to the better keeping 
kinds only. Softer varieties must be cooled quickly, as their life 
is shorter, and too much deterioration will take place during 
cooling process if handled as suggested above.] 

Apples are sometimes frozen in the storage rooms owing to 
a considerable drop in the temperature or to a poor distribution 
of the cold air. If the fruit compartment adjoins a freezer room 
and the insulation is poor, the fruit may be frozen in packages 
piled close to the freezer wall. Apples placed near the refriger- 
ating pipes or near the cold-air duct where it enters the room 
may be injured by freezing if the plant is improperly installed or 
managed: or if the piping or air circulation is faulty, the tem- 
perature at the botton may be lower than that at the top of the 

The frosting of the fruit does not necessarily injure it. 
When the apple freezes, the water in the cells is withdrawn and 
frozen in the intercellular spaces, and if it thaws slowly and the 
freezing has not been too severe, the cells may regain the water 
without injury and resume their living function. If the thawing 
is rapid, the cells may not reabsorb the water with sufficient 
rapidity, and in this case it remains in the intercellular spaces 
and is lost by evaporation. In addition, the tissues next to the 
area of greatest freezing may be forced apart by the formation 
of ice crystals in the intercellular spaces. 


If the freezing is so severe as to withdraw too much of the 
cell water, the cells may not be able to absorb it and will be killed 
in the same manner as if dried out in any other way. Occasion- 
ally the freezing is so rapid that besides the withdrawal of water 
the cell contents are disorganized or possibly frozen outright; 
at any rate, the cell may be directly killed by a sudden change of 
temperature. It is probable that varieties may differ as to the 
degree of freezing they will stand without injury, and further, 
that the same sort may vary in this respect when grown under 
different conditions or subjected to different treatment. 

The most characteristic results of injurious freezing are a 
translucent appearance of the skin of the fruit, a water-logged 
and springy or spongy condition of the flesh, a forcing apart of 
the tissues, and a brownish discoloration of the flesh. The brown- 
ing may result from any cause which results in the death of the 
cells and is not necessarily characteristic of freezing. It often 
happens that the skin of the fruit retains its normal brightness 
after the interior has discolored. 

In the practical handling of frozen stock, the temperature 
should be raised very slowly until the frost is withdrawn. If 
possible, the fruit should not be moved until it is defrosted, as 
it discolors quickly wherever a slight bruise occurs, or even where 
the skin is lightly rubbed. With these precautions observed it 
is often possible to defrost stock that is quite firmly frozen with- 
out apparent injury to it. 


In the storage investigations under discussion a comparison 
has been made between wrapped and unwrapped stock on the 
keeping quality of the fruit, and the efficiency of different kinds 
of paper for wrappers — tissue, parchment, w^axed or paraffin, 
and unprinted news — has been tested. A box of unwrapped fruit, 
with packages of fruit wrapped with the kinds of paper mentioned 
in order above, is shown in Fig. 3. 

It has been found that the wrapper may influence the keep- 
ing quality in several different ways. It extends the life of the 
fruit beyond its normal period by retarding the ripening processes. 
The influence of the wTapper in this regard is apparent especially 
at the end of the normal storage season of the naked fruit when 



the flesh begins to grow mealy from overripeness. At this time 
the wrapped apples may be firm and remain in prime condition 
for several weeks or even months. The wrapper is especially 
useful in extending the season of early winter sorts, or in making 
the long-keeping varieties available for use over a still longer 
period of time. 

The wrapper may be useful in preventing the transfer of 
rot from one apple to another. If the fungous is capable of 
growing in the storage temperature, it is not likely that the wrap- 
per retards its growth, but when the spores develop they are 
confined within the wrapper and their dissemination is difficult 
or impossible. 


The importance of a wrapper in protecting the fruit from 
decay and in extending its season may be better appreciated by 
reference to the following table : 













Per cent. 


Per cent. 
15.0 , 





, Wealthy . 

Per cent. 


Per cent. 

Mcintosh ... 
(second lot) 



The wrapper protects the apple against bruising and the dis- 
coloration that may result from improper packing or rough han- 
dling; it checks transpiration, and by the preservation of the at- 
tractive appearance and firmness of the fruit adds to its com- 
mercial value. 

No important difference was noticeable in the eflficiency of 
the different wrappers, except that a mold developed freely on 
the parchment paper in a temperature of 36° F. This mold grew 
only to a slight extent in 32° F. 

A double wrapper is more efficient in retarding ripening and 
transpiration than a single wrapper. A good combination con- 
sists in a porous news paper next to the fruit, with an impervious 
wax or paraffin wrapper on the outside. The wrappers vary in 
cost from 20 cents per thousand for news papef, 9XT2 inches, to 
70 cents per thousand for the better grades of paraffin. 


Preliminary studies have been made on the influence of cult- 
ural and other conditions surrounding the growing fruit on its 
storage quality. Considerable data along this line will be brought 
out in the comparison of the same variety grown in different sec- 
tions. It has been observed that the Tompkins King, Hubbards- 
ton, and Sutton apples from rank-growing young trees ripen 
faster than smaller fruit from older slower-growing trees, and 
therefore reach the end of their life history sooner. From older 
trees these varieties have kept well till the middle of April, while 
from young trees the commercial storage limit is sometimes three 
months shorter. 

It has been noticed that Rhode Island Grceuing apples from 
old trees remain hard longer than the same variety from young 
trees, but the greener condition of the fruit from the older trees 
when picked at the same time made it more susceptible to scald. 
Rhode Island Greenings from Mr. Grant G. Hitchings, South 
Onondaga. X. Y., showed 50 per cent of scald from young trees 
on April 28, 1903. and S2 per cent in smaller, greener fruit from 
older trees. 

Rhode Island Greening. Mann, and Baldwin apples grown 
on sandy land ripened more rapidly than similar fruit from clay 
land, where all of the other conditions of growth were similar. 




Fig. 4 shows the average condition of Baldwin apples on April 
28, 1903, grown on sandy and clay soil in the orchard of Mr. W. 
T. Mann, Barker, Niagara County, N. Y., and stored in a tem- 
perature of 32° F. The upper apple was grown on clay; the 
lower, on sandy soil. 

This fruit was picked in October, 1902, and was stored soon 
after picking. The fruit from the heavy clay soil was generally 
smaller and was much less highly colored. Both lots kept well 
throughout the storage season. The fruit from the sandy land 
was riper at the end of the storage season, better in quality, and 
worth more to the dealer and to the consumer. 

The subject will require critical study over a period of years 
before it will be possible to fully understand the influence of 
various cultural, climatic, and other conditions of growth on the 
life processes in the fruit. 


The principal storage packages for apples are barrels of 
about 3 bushels capacity and boxes holding 40 to 50 pounds. 
The larger the bulk of fruit and the more it is protected from 
the air the longer it retains the heat after entering the storage 
room. If the fruit is hot and the variety a quick-ripening sort, 
it may continue to ripen considerably in the center of the package 
before the fruit cools in that position. The long-keeping varie- 
ties that are harvested and shipped in cooler weather are less 
likely to show the effect of the type of the package. The smaller 
package therefore presents distinct advantages for the early, 
quick-ripening varieties and is most useful in the hottest weather, 
as the fruit cools down quickly throughout the package and its 
ripening proceeds uniformly. 

There is a wide difference of opinion concerning the com- 
parative value of ventilated and closed packages for apple stor- 
age. The chief advantage of the ventilated package appears to 
lie in the greater rapidity with which its contents cool off, and 
its value in this respect depends on the amount of ventilation in 
the package. The contents of an ordinary ventilated apple barrel 
do not cool much more quickly than the contents of a closed bar- 
rel, and the value of the ventilated barrel for the purpose for 
which it is designed is somewhat doubtful. 


Apples in a ventilated package are likely to shrivel if the 
fruit is stored for any length of time. In the ordinary ventilated 
apple barrel the exposure is not sufficient to affect the fruit to any 
extent, but in boxes in which there is much exposure the fruit 
may be corky or spongy in texture if held until spring. 

The size of the package may have an important influence on 
the length of the storage season. Its influence in this respect is 
especially marked when the fruit begins to mellow in texture. 
Barrel stock in this condition needs to be sold to prevent the 
bruising of the fruit from its own weight, but apples equally ripe 
may be carried in boxes safely sometimes for several weeks 


There is a general impression that cold-storage apples deter- 
iorate quickly after removal from the warehouse. This opinion 
is fovmded on the experience of the fruit handler and the con- 
sumer, but the impression is not generally applicable to all stor- 
age apples. In fact, it is probable that storage apples do not de- 
teriorate more quickly than other apples that are equally ripe and 
are held in the same outside temperature. If the fruit is overripe 
when taken from storage — and a good deal of stock is stored 
until it reaches this condition — it naturally breaks down quickly ; 
but firm stock may be held for weeks and even months after it 
has been in storage. [This is confirmed by the author's expe- 
rience, and applies not only to apples, but also to other goods 
which are cold stored. The popular idea that cold storing goods 
weakens them for exposure to ordinary temperatures after being 
removed from storage is largely erroneous. If the temperature 
is not lowered too suddenly when the goods are stored nor raised 
too quickly when the goods are removed from storage they will 
have nearly the same vitality for rough usage that they would 
have had originally if never placed in cold storage. Avoid sud- 
den changes in temperature. See experiment described in chapter 
on ** Eggs m Cold Storage."] 

The rapidity of deterioration depends also on the tempera- 
ture into which the fruit is removed. The following table shows 
the amount of decay in Baldwin apples from the same barrel after 
removal and subjection to different temperatures: 






Date re- 
moved from 


Date in- 

Per cent rot. 


44'' F. 



67" F. 


Jan. 29 

Jan. 29 

Feb. 10 



Feb. 13 



Feb. 16 



Feb. 20 




Mar. 3 



Mar. 7 
Mar. 24 



Apr. 6 


Late in the spring the fruit is far advanced in its life and 
the weather is becoming warmer. All apples similarly ripe, 
whether in cold storage or not, break down more quickly at this 
time than in the winter. 

In commercial practice the dealer often holds the apples for 
a rise in price, and finally removes them from the warehouse, 
not because the market has improved, but for the reason that he 
finds that a longer storage would result in serious deterioration 
from fruit rots and overripeness. When a considerable amount 
of stock is decayed on removal from the warehouse the evidence 
is conclusive that the apples should have been sold earlier in the 
season. In the purchase of cold-storage stock the consumer will 
have little cause to complain of the rapid deterioration of the 
fruit if he exercises good judgment in the selection of apples that 
are still sound and firm. 


Apples do not improve in grade in cold storage. In han- 
dling a crop too much care can not be given to grading the fruit 
properly before it enters the storage house. The contents of 
many packages are injured by the spread of disease from a few 
imperfect apples. Rots enter the fruit most easily wherever the 
skin is bruised or broken, and in the early stages of the rot devel- 
opment it is common to see the diseases manifesting themselves 
around worm holes or bruises occasioned by rough handling. 



from nails that protrude through the barrels, or from other 

When the crop is light it may pay to store apples that are 
not of the first grade, but such fruit should be rigidly eliminated 
from the best stock and stored where it can be removed earlier 
in the season than the better qualities. 

The attractiveness and the value of the best fruit is often 
injured by careless handling. A bruised spot dies and discolors. 
Finger marks made by pickers, graders, and packers, and injuries 
from the shifting of the fruit in transit or from rough handling, 
become more apparent as the season advances. In fact, all of the 
investigations of the Department of Agriculture emphasize the 


FIG. 6. — ''slack" PACKED NORTHERN 

fundamental importance of well-grown, carefully handled fruit 
in successful storage operations. 

Fig. 5 shows a wtII packed barrel of Esopus Spitzcnbnrg 
apples removed from storage in March, 1903. The fruit was 
properly packed in the orchard and repacking was not needed 
when the fruit was sold. 

Fig. 6 shows a " slack " packed barrel of Northern Spy 
apples removed from storage in March, 1903. The fruit was not 
packed firmly in the orchard. It settled in the barrel, leaving it 
*' slack " when removed from storage. Barrels in this condition 
need to be repacked. The fruit is easily bruised and it deteri- 
orates more quickly in the storage house and after removal when 
it is loosely packed. 



When some varieties of apples reach a certain degree of 
ripeness the part of the fruit grown in the shade often turns 
brown, not unlike the color of a baked apple. This difficulty does 
not extend deep into the flesh, but it detracts from the appear- 
ance of the fruit and reduces its commercial value. This trouble 
is commonly called "apple scald." It may appear in fruit held 
in common or in cold storage. 

The exact nature of scald is not well understood, though 
apple men have many theories by which its appearance is popu- 
larly explained. The most common theory gives rise to the name 
of scald — that is, the brown, cooked appearance is thought to be 
due to the overheating of the fruit when it is stored, or to a tem- 
perature too low for the variety, or to picking the fruit when too 
ripe; and other matters relating to the growth and handling of 
the fruit are thought to develop it. 

As the scald is an important commercial problem it has been 
considered from several standpoints in the fruit-storage investi- 
gations of the Department. The nature of the scald, the influ- 
ence of the degree of maturity of the fruit when picked, of com- 
mercial methods of handling, of fruit wrappers, of different tem- 
peratures, and of cultural conditions on its development are 
among the problems investigated. 

Apple scald is not a contagious disease. According to Dr. 
A. F. Woods, Pathologist and Physiologist of the Department of 
Agriculture, it is a physiological disturbance not connected in 
any way with the action of parasitic or saprophytic organisms 
such as molds or bacteria. Briefly, it is the mixing of the cell 
contents or premature death of the cells and their browning by 
oxidation through the influence of the normal oxidizing ferments 
of the cell. There are many conditions which influence the de- 
velopment of this trouble. It appears to be closely connected 
with the changes that occur in ripening after the fruit is picked, 
and is most injurious in its eflPects as the fruit approaches the 
end of its life. Several of the factors that influence it will be dis- 
cussed. Fig. 7 shows scald en a Rho<le Island Greening apple. 
The cross section shows that the scald is a surface trouble only. 

The scald always appears first on the green or less mature 
side of an apple, and if the fruit is only partly ripe it may spread 






entirely over it; but the portions grown in the shade and under- 
colored are first and most seriously aflFected. The upper speci- 
men in Fig. I shows the distribution of scald on an immature 
York Imperial apple in March, 1903. The apples that are more 
mature and more highly colored when picked are less susceptible 
to injury, and the side grown in the sunlight may remain en- 
tirely free from it. The lower specimen in Fig. i (picked from 
the same tree at the time, October, 1902, when the upper. speci- 
men was picked) shows a well-colored York Imperial apple and 
its freedom from the scald is noticeable. A trace only is shown 
on the right-hand side of the apple, where the color is not as 
dark as elsewhere. 

When the apple crop is picked before it is mature the fruit 
is more susceptible to scald than it would have been later in the 
seastm. The relative susceptibility of immature and more ma- 
ture apples is brought out in the table following. The fruit was* 
picked two weeks apart. At the first picking the apples were 
l)artly colored, or in the condition in which a large proportion 
of the commercial apple crop is harvested. At the second picking 
the fruit was more mature, with better color, but still hard. The 
(litTerences in ripeness are fairly represented in the fruit in Figs. 
I and 2, The percentages do not represent the relative suscepti- 
bility of the different varieties to scald, as the fruit was grown 
in different States and the observations were made at different 
times. The percentages show the average amounts of scald in 
fruit stored at temperatures of 31° to 32*" F. and 34° to 36 '^ F. 



Locality f(rovrn. 






/; r . . «/, 


New York 



Hon Oavis 

. . Illinois 



KIuhIo Isl.ind i/».\ ^:\i. 
Voilow NewtvAvn 
York Iti^iHMial 

; . New York 

. . IKinv^is ... 
. . ViTXiuia 














In the practical handling of orchards the fundamental cor- 
rective of scald lies in practicing those cultural and harvesting 
methods that develop maturity and a highly colored fruit. These 
methods have already been briefly discussed. The picking of the 
fruit when too green, dense-headed trees that shut out the sun- 
light, heavy soil, a location or season that causes the fruit to 
mature later than usual and makes it still green at picking time — 
these are among the conditions that make it particularly suscep- 
tible to the development of the scald. 

After the fruit is harvested its susceptibility increases as its 
ripening progresses. Early in the storage season the scald may 
not appear, but later the same variety may have developed enough 
to injure its commercial value. The amount of scald at different 
periods of the season on the same lot of Baldwin apples stored at 
32° F. is brought out in the following statement : 


Per cent. 

January 29, 1903 

February 21, 1903 

March 20, 1903 20 

April 21, 1903 23 

It should be the aim of the apple storer to remove the fruit 
from storage before a variety normally begins to scald, and to 
hold until late in the season only those sorts that do not scald. 


The temperature that checks the ripening to the greatest 
degree also retards the appearance of the scald. In some of the 
apple-growing sections it is quite generally believed that bad 
scalding varieties should be stored in a temperature of 36° to 
38° F., and that a temperature as low as 32° F. hastens its devel- 
opment. The investigations of the Department have shown that 
this impression is not well founded, but on the contrary they indi- 
cate that the scald develops more freely in the higher tempera- 
ture. To illustrate, one lot of York Imperial apples, a variety 
which is greatly affected by scald, had developed 16.9 per cent 
of this trouble by January 22, 1902, in a temperature of 36** F., 
while a similar lot stored in a temperature of 32** F. developed 
only 3.4 per cent. One lot of Rhode Island Greening apples by 
February 3, 1903, had developed 21 per cent in 32** F., while a 



similar lot, in 36° F., showed 55 per cent. In the case of the 
Sutton apple, investigation showed 25 per cent of scald in apples 
stored at 32°, and 42 per cent when stored at 36** F. 

If the fruit is stored as soon as it is picked, or is shipped in 
refrigerator cars or in cool weather, and if it has been handled 
in the most careful manner, the ripening may not proceed much 
more rapidly and the scald may not develop more freely in the 
higher than in the lower storage temperature. 

When the fruit is removed from the storage house the scald 
sometimes develops rapidly. Its appearance at this time seems 
to depend on at least two important conditions — the ripeness of 
the fruit and the temperature into which it is taken. Late in the 
storage season the scald is most severe; first, because the fruit 
is more mature, and, second, for the reason that the warm weather 
prevailing at that season develops it quickly. [It is suggested 
that scald develops much more rapidly in case the fruit is allowed 
to rise in temperature suddenly. When removed from storage, 
apples, as well as other goods, should not be exposed at once to 
comparatively high temperatures. — Author.] 

The development of the scald also seems to be influenced by 
the amount of humidity in the air. So long as the fruit remains 
cold and condenses the moisture of the atmosphere upon it the 
scald is retarded more than in a dry air of the same temperature. 

The accompanying table shows the rapidity with which the 
scald may develop on Baldwin apples when portions of the same 
barrel are removed to different temperatures. There was no in- 
crease in the amount of scald in any of the lots after nine days. 








Date re- 
moved from 
' storage. 

Date in- 

Per cent of scald. 

44" F. 48« F. 61" F. 67« F. 



Jan. 29 

Jan. 29 


Feb. 3 


Feb. 4 

' do 

Feb. 6 

Feb. 7 















The upper specimen in Fig. 8 shows the average condition 
of a lot of Wagener apples in March, 1903, having been picked 
in October, 1902, and stored at a temperature of 32° F. There 
was no scald on the apples when removed. Forty-eight hours 
later, after the fruit had been in a temperature of 70** F., the 
light-colored portion of the apples was badly scalded, as shown 
in the lower apple. Late in the storage season the fruit is more 
susceptible to scald, and a high temperature when the fruit is 
removed from the storage house may develop it quickly. 

It should be the aim of the fruit storer not only to remove 
the fruit before the scald normally appears, but to hold the ap- 
ples after removal in the lowest possible temperature to prevent 
its rapid development. 


The ripening of the fruit between the time of picking and its 
storage increases its susceptibility to scald. 

When the picking and shipping seasons are cool and dry it 
may be possible to delay the storage of the fruit for some time 
without injury so far as the predisposition to scald is concerned. 
In the investigations of 1901-2 in western New York there was 
no apparent injury from delaying the storage, but the weather 
conditions at this period were ideal for apple handling. 

The scald develops seriously when the storage of the fruit 
is delayed in hot weather. Detentions in the orchard, in transit 
in closed cars, in unloading at the terminal, or in the warehouse 
cause the fruit to ripen quickly and favor the rapid growth of 
the fruit rots, as they bring the fruit much nearer the end of its 
life before it enters the storage room. Under these circumstances 
the fruit may scald badly, mellow early in the season, and rot, 
and no storage treatment can correct the abuses to which it has 
been subjected. 

The following table brings out the injury that may be caused 
by delaying the storage of the fruit in hot weather. The mean 
average temperature between September 15 and 30, 1902, was 
about 62° F. and the mean average humidity about 84°. Fruit 
picked from the same trees on October 4, 1902, and stored two 
weeks later, when the temperature was about 53*^ F. and the 
humidity about 80°, was not injured by the delay. The apples 



referred to were grown in eastern New York and stored in Bos- 
ton, and these records were taken the following February. 



Picked Picked | 

I Sept. 12, Sept 15, Picked Oct. 4, I Picked Oct. 5, 

1902, stored stored ' stored Oct. 9. stored Oct. 19. 

' Sept. 15. I Sept. 30. I 

Rhode Island Green 



Tompkins King 

Per cent. , Per cent. 


Per cent. 

Per cent. 



(No record) (No record) 
o I o 

o j o 


The influence of the various fruit wrappers mentioned has 
been studied in connection with the scald. Sometimes the wrap- 
pers retard it to a slight degree, but often the trouble is as severe 
or more severe in the wrapped fruit. Whenever the wrapper has 
been effective in retarding the scald the wax or paraffin paper 
was most useful. 

The following table gives a comparison between wrapped 
and unwrapped fruit, and emphasizes the fact that for commer- 
cial purposes the wrapper should not be looked upon as an affect- 
ive means of preventing the trouble. The records of each variety 
are based on 8 to 32 bushels of fruit, one-half of which was 




Ben Davis 




Rhode Island Greening. 



New York 





New York . 



York Imperial Virginia. 


Per cent. 









Per cent^ 








All varieties are not equally susceptible to scald, and there 
appears to be a wide difference in the amount developed in the 
same variety grown in different parts of the country. While the 
light-colored portion of an apple is more susceptible than the 
more highly-colored part, it does not follow that green or yellow 
varieties are more susceptible than red ones. Of the important 
commercial sorts used in the investigations of the Department 
of Agriculture, the varieties named in the subjoined list have 
proved most susceptible. The season when the scald is most 
likely to appear is given with each kind, though there may be a 
wide variation from year to year. The time of the appearance 
of the scald is influenced to an important degree by the method 
of handling the fruit and by its degree of ripeness. 

Arctic, serious, midwinter. Smith, Cider, serious, early 
Arkansas, often serious, after winter. 

midwinter. Stayman Winesap, sometimes 
Baldwin, often serious, late in serious, midwinter. 

season. Wagener, serious, midwinter. 

Ben Davis, often serious, late White Doctor, serious, mid- 

in season. winter. 

Gilpin, often serious, late in White Pippin, slight, late in 

season. season. 

Green Newtown, slight, late in Willow, slight, late in season. 

season. Winesap, often serious, late in 
Grimes, serious, early winter. season. 

Huntsman, serious, midwinter. Yellow Newtown, slight, late 
Lankford, serious, midwinter. in season. 

Nero, serious, midwinter. York Imperial, serious, mid- 
Paragon, sometimes serious, winter. 

midwinter. York Stripe, slight, late in 
Ralls, slight, midwinter. season. 

Rhode Island Greeninp. se- 
rious, midwinter. 


A large number of varieties of apples grown under various 
conditions were under observation by the Department of Agri- 
culture. It was tlie purpose of the investigation to determine the 
keeping quality of the varieties during the commercial apple- 
storage season, which usually terminates May i. or shortly after- 
wards. It was not attempted to carry the varieties longer than 
the apple-storage season, though many of them when finally 
taken from the storage house were in prime condition and would 
have kept well for a longer period. 


There is a wide difference in the keeping quality of the same 
variety when it is grown in different parts of the country. There 
is a striking variation also in the behavior of the same variety 
when it is grown in the same locality under different cultural 
conditions and in different seasons. There may be a permanent 
difference in the keeping quality of the apples of one region when 
compared with those of another, but it is not safe to draw general 
conclusions in this regard until the varieties of each have been 
under observation during several seasons and have been grown 
under different cultural conditions. No attempt was made in the 
investigations to draw comparisons between the keeping quality 
of the same sort from different places. The behavior of each lot 
is given in commercial terms rather than in detailed notes, so 
that the grower or apple handler may know something of the 
storage value of a variety under the conditions in which it has 
been observed by the Department of Agriculture. The fruit was 
stored in bushel boxes in a temperature of 30° to 32** F. 


A statement follows, summarizing the orchard conditions in 
which the fruit used in the experiments of the Department of 
Agriculture was grown. In the variety catalogue each sort is 
credited to the grower from whom it was received : 

BoGGS, A. H., Waynesville, Haywood County, N. C, 1902: 

Clay loam, stony, with clay subsoil ; altitude, 3,000 to 3»50O feet ; trees, 
12 to 15 years old; thoroughly sprayed; sod culture. 
Bradley, F. L., Barker, Niagara County. N. Y., 1902: 

Sandy loam, with clay subsoil; altitude, about 300 feet; sprayed; 
tillage ; on Lake Ontario. 
Brown, J. E., Wilson, Niagara Count3% N. Y., 1901 : 

Sandy loam, with sandy loam subsoil ; altitude, about 300 feet ; trees, 
40 years old; sprayed; tillage; on Lake Ontario. 
Derby, S. H., Woodside, Kent County, Del., 1902: 

Sandy, with clay-loam subsoil; altitude, about 60 feet; trees, 10 to 
25 years ; thorough spraying and tillage ; annual use of clover cover 
crops ; trees unusually vigorous. 
DoDD. G. J., Greenwood, Jackson County, Mo., 1902: 

Black prairie soil, with clay subsoil ; altitude. 1,000 feet; trees, 18 
years old, except Ben Davis, 11 years; sprayed; sod culture after 
treea were 7 years old. 
DuNLAP. H. M., Southern Illinois, 1901 : 

Fruit from orchards in southern Illinois ; data not available. 
Flournoy, W. T.. Marionville. Lawrence County, Mo., 1902: 

Heavy clay, with rocky limestone clay subsoil ; altitude, about 1,250 
feet; age of trees, 7 years; spraying and tillage. 


Gilbert, Z. A., Farmington, Franklin County, Me., 1902: 

Granite drift, with so-called pin-gravel subsoil ; altitude, about 365 
feet ; age of trees, 20 years ; no spraying or tillage ; land top dressed 
with wood ashes. 
HiTCHiNGS, Grant G., South Onondaga, Onondaga County, N. Y., igoi 
and 1902: 
Clay loam, stonj', with heavy red clay or gravel-and-clay subsoil ; 
altitude, about 1,200 feet; age of trees, 4 to 100 years; sprayed; 
sod culture, with grass left in orchard for mulch. 
HuTCHiNS, Edward, Fennville, Allegan County, Mich., 1902: 

Clay loam; altitude, 700 feet; age of trees, about 35 years; sprayed; 
Kansas Agricultural Experiment Station, Manhattan, Riley County, 
Kans., 1901 : 
Clay loam, with clay subsoil; altitude, about 1,000 feet; age of trees, 

ID years : spraying and tillage. 
Orchards near the experiment station, 1901 : Soil and altitude same 
as above ; no spraying or tillage ; fruit received through Kansas Sta- 
LuPTON, S. L., Winchester, Frederick County, Va., 1901 and 1902: 

Clay loam, with red clay subsoil; altitude, 750 feet; age of trees, 8 
years; sprayed: sod culture, grass cropped. 
Maine Agricultural Experiment Station, Orono, Penobscot County, 
Me., 1901 : 
Sandy loam, with clay subsoil; altitude, about 150 feet; age of trees, 

10 to 12 years; sprayed; clean culture, with fall cover crop of rye. 
Mann, W. T., Barker, Niagara County, N. Y., 1902: 

Clay loam, with clay subsoil, and sandy loam with sandy subsoil; al- 
titude, about 300 feet ; age of trees, about 30 years ; sprayed thor- 
oughly; tillage; clover cover crops. 
Massachusetts Agricultural College Experiment Station, Amherst, 
Hampshire County, Mass., IQ02: 
Gravelly soil, with clay subsoil, moist; altitude, 250 feet; age of trees, 
30 years; sprayed; tillage. 
Michigan Agricultural College Experiment Substation, South Haven, 
Van Buren County, Mich., 1902: 
Rich, sandy loam, with clay subsoil; age of trees, 9 to 14 years; al- 
titude, 625 feet ; on Lake Michigan ; spraying and cultivation thor- 
Miller, W. S., Gerrardstown, Berkeley County, W. Va., 1901 : 

Soapstone, derived from Romney shale, clay subsoil; altitude, 700 
feet; age of trees, 12 to 26 years; sprayed and cultivated. 
New York State Experiment Station, Geneva, Ontario County, N. Y., 
1901 and 1902: 
Rather heavy clay loam, with heavy clay subsoil; altitude, about 600 
feet; age of trees, generally from 15 to 25 years; sprayed and cul- 
tivated with cover crops. 
Ozark Orchard Company, Goodman, McDonald County, Mo., 1901 and 
Flinty clay, with clay, shale, or gravel subsoil; altitude, 1,250 feet: 
age of trees, 6 years ; sprayed and cultivated. 
Powell, George T., Ghent, Columbia County, N. Y., 1902: 

Gravelly loam, with clay-gravelly subsoil ; altitude, about 400 feet : 
age of trees, 35 to 45 years, except Tompkins King and Lady Sweet 

1 1 years, Sutton 8 years, Hubbardston 5 years ; spraying and culti- 
vation thorough, with clover cover crops annually. 


Reeks, M., Douglas, Allegan County, Mich., 1902: 

Clay loam, with* clay subsoil several feet below surface; age of trees, 
12 to 15 years; sprayed and cultivated; altitude, 650 to 675 feet. 
Spohr, G. E., Manhattan, Riley County, Kans., 1901 : 

Sandy loam, with sandy subsoil; altitude, about 950 feet; age of 
trees, about 20 years, except Jonathan 10 years ; no tillage or spray- 
ing; fruit received through Kansas Experiment Station. 
Speakman, F. H., Neosho, Newton Coimty, Mo., 1901 : 

Clay loam, gfravelly and stony, with red clay subsoil, mixed with flint 
stone; altitude, 1,100 feet; age of trees, 12 years; sprayed and culti- 
Taylor, J. F., Douglas, Allegan County, Mich., 1902: 

Sandy loam, with clay subsoil 15 feet below surface; altitude, 650 to 
675 feet; from 8-year top grafts on stocks of "Cannon Redstreak," 
25 years old ; sprayed and cultivated. 
Virginia Agricultural Experiment Station, Blacksburg, Montgomery 
County, Va., 1901 : 
Rather heavy, mostly of limestone origin, with some sand, not stiff, 
subsoil of same nature but heavier; altitude, 2,170 feet; age of trees, 
12 years ; sprayed but not cultivated in 1901. 
Wellhouse, F., Tonganoxie, Leavenworth County, Kans., 1901 : 

Rich prairie loam, with red clay subsoil, with some sand; altitude, 
about 900 feet ; age of trees, 7 years ; not sprayed but cultivated. 


Bulletin No. 48 gives a very complete list of varieties used 
in the investigations, with comparative keeping qralities in cold 
storage. Prof. Powell has at the request of the .' uthor selected 
some of the most important as follows : 

Arkansas. Synonyms: Blackiwig, Mammoth Blacktwig. 

W. S. Miller, Gerrardstown, Berkeley County, W. Va. : Hard, No. 

i; picked October 12, 1901, stored October 18; May i, 1902, bright, 

firm, and sound, no rot or scald. 
Ozark Orchard Company, Goodman, McDonald County, Mo. : No. 

2 stock; badly affected with "flyspeck" fungus; picked October 11, 

1902, stored October 28; March 10, 1903, shriveled, considerable 

rot, no scald. 
Virginia Agricultural Experiment Station, Blacksburg, Montgomery 

County, Va.: Small, sound; picked September 26, 1901, stored 

October 6; May i, 1902, firm, no decay, nearly all slightly scalded 

on light side. 

F. L. Bradley, Barker, Niagara County, N. Y. : Mixed grade, dull, 

scabby: picked October 9, 1902, stored October 15; May i, 1903, 

firm, no scald or rot. 
J. K Brown, Wilson, Niagara County, N. Y. : No. i, fair color; 

picked October 8, 1901, stored October 15; May i, 1902, firm, no 

rot, slight scald. 
H, M. Dunlap, Southern Illinois: Firm, somewhat wormy; picked 

October 8, 1901, stored October 10; March 18, 1902, commencing 

to scald and decay. 
Z. A. Gilbert, Farmington, Franklin County, Me.: Medium sized, 

dull colored; date of picking undetermined, stored November 10. 

1902; May I, 1903. firm, no decay or scald. 


G. G. Hitchings. South Onondaga, Onondaga County. N. Y. : Large, 
dark red, No. i ; trees 12 years old ; picked October i, 1902, stored 
October 4; May i, 1903, firm, no scald or rot. 

W. T. Mann, Barker, Niagara County, N. Y. : Hard, finely colored, 
No. i; picked October 16, 1902, stored October 18; May i, 1903. 
hard, no scald or rot- 
Massachusetts Agricultural College Experiment Station, Amherst, 
Hampshire County, Mass. ; Dull greenish red. No. i ; picked Oc- 
tober II, 1902, stored October 15; May i, 1903, no scald or rot, 

New York State Experiment Station, Geneva, Ontario County, N. Y. : 
Hard, light colored, small ; picked October 12. 1902, stored October 
15; May I, 1903, hard and sound: similar in 1901. 

G. T. Powell, Ghent, Columbia County, N. Y. : Bright, well colored. 
No. t; picked October 16, 1902, stored October 19; May i, 1903, 
firm condition, no scald or decay. 

Virginia Experiment Station, Blacksburg, Montgomery County, Va. : 
Firm, light colored. No. i; picked September 26, 1901, stored 
October 6; May i, 1902, semi-firm, no scald or decay; kept unus- 
ually well for a northern variety and was of much better grade and 
color than most of the other sorts from same source. 
Ben Davis. 

G. J. Dodd, Greenwood, Jackson County, Mo. : Hard, w^ell colored, 
No. I ; picked October i, 1902, stored October 4; March 10, 1903, 
in good market condition; scald and rot slight. 

H. M. Dunlap. Southern Illinois : No. i stock ; picked October 8, 

1901, stored October 10; Marchr 18, 1902, in fair market condition; 
somewhr.: injured by scald and decay. 

G. G. Hitcl.Ings, South Onondaga, Onondaga County, N. Y. : Hard, 
medium >lzcd, highly colored; trees 12 years old; picked October 
2J. 1901, stored October 26; May i, 1902, firm and sound, no scald. 

S. L. Lupton. Winchester, Frederick County, Va. : Firm, light col- 
ored, worm> ; picked October 4, 1901, stored October 12 ; March 27, 

1902, consider?.ble scald, decay slight. 

Massachusetts Agricultural College Experiment Station, Amherst, 
Hampshire County, Mass. : Small and hard ; picked October 13, 
1902, stored October 15; May i, 1903. firm and sound. 

W. S. Miller, Gerrardstown, Berkeley County, W. Va. : Firm, well 
colored. No. i; picked October 2, igoi, stored October 18; May i, 
1902, firm, no rot or scald. 

New York State Experiment Station, Geneva, Ontario County, N. Y. : 
Small, hard, light colored; date of picking undetermined, stored 
November 12, 1902; May i, 1903, semi-firm, no scald or decay; 
similar in 1902. 

Ozark Orchard Company, Goodman, McDonald County, Mo.; Me- 
dium to very large, well colored; picked October 10. 1902, stored 
October 28; March 10, 1903, overripe, slightly wilted, considerable 

F. H. Speakman, Neosho. Newton County, Mo. : Sound, well col- 
ored, No. i; picked October 24, 1901, stored October 28; March 20, 
1902. in good market condition, slight rot and scald. 

G. E. Spohr, Manhattan, Riley County, Kans. : Small, poorly colored ; 
picked October 11, 1901, stored October 18; March 20, 1902, badly 
shriveled, no decay or scald ; received through Kansas Experiment 

Virginia Agricultural Experiment Station, Blacksburg. Montgomery 
County, Va. : Small, well colored, somewhat wormy ; picked Sep- 


tember 26, 1901, stored October 8; May i, 1902, semi-firm, no scald, 

decay slight. 
Black Gilliflower. Synonym: GilliAower. 

G. G. Hitchings, South Onondaga, Onondaga County, N. Y. : Light 

colored, No. i; trees about 100 years old; picked October i, 1902, 

stored October 4; May i, 1903, in prime commercial condition; 

similar for fruit picked in 1901. 
Massachusetts Agricultural College Experiment Station, Amherst, 

Hampshire County, Mass. : Dull colored. No. 2 ; picked October 10, 

1902, stored October 15; firm until January i, 1903; decayed badly 

after February i, 
G. T. Powell. Ghent, Columbia County, N. Y. : Well colored, No. i ; 

picked October 16, 1902, stored October 19; February i, 1903, badly 

injured by rot. 
Esopus. Synonyms: Esopus Spitzenhurg; Spitsenburg. 

F. L. Bradley, Barker, Niagara County, N. Y. : Scabby and poorly 
colored; picked' September 27, 1902, stored October 3; firm until 
March i, 1903. when the fruit commenced to decay around scab 

G. G. Hitchings, South Onondaga, Onondaga County, N. Y. : Dark 
red. No. i ; trees about 100 years old ; picked October i, 1902, stored 
October 4; May i, 1903, firm, no scald or decay. 

New York State Experiment Station, Geneva, Ontario County, N. Y. : 
No. I ; picked October 21, 1902, stored October 27 ; May i, 1903, 
semi-firm, no decay or scald ; in barrels should be sold April i. 

G. T. Powell, Ghent, Columbia County, N. Y. : Well colored, No. i ; 
picked October 16, 1902, stored October 19; in prime commercial 
condition until April i, 1903, after which the fruit began to mellow; 
no rot. 

The flesh of this variety becomes mealy when overripe. 
Fall Pippin. 

Massachusetts Agricultural College Experiment Station, Amherst, 
Hampshire County, Mass. : Large, bright. No. i ; picked September 
30, 1902, stored October 3; in firm condition until January i, 1903, 
when the fruit began to mellow. 

New York State Experiment Station, Geneva, Ontario County, N. Y. : 
Bright, No. i; picked September 24, 1902, stored September 29; 
January 27, 1903, commencing to soften; fruit picked in 1901 kept 
in good condition until January 10, 1902; may be held in boxes 
till February i. 
Fameuse. Synonym : Snow. 

G. G. Hitchings, South Onondaga, Onondaga County, N. Y. : Well 
colored. No. i ; trees 12 years old ; picked October 7, 1902, stored 
October 12; in good commercial condition until March 15, 1903. 
Fruit picked in 1901 kept in good condition until February 15, 1902. 

Maine Agricultural Experiment Station, Orono, Penobscot County, 
Me. : Slight colored. No. i ; ripe and somewhat bruised ; picked 
October 7, 1902, stored October 24; January 23, 1903, in good condi- 
tion for box storage, no scald or decay; March 11, overripe and past 
commercial condition. 

Massachusetts Agricultural College Experiment Station, Amherst, 
Hampshire County, Mass. ; Bright, No. i ; picked September 30, 1902, 
stored October 3; February 15, firm, no scald or rot; commercial 
limit about March i. 

New York State Experiment Station, Geneva, Ontario County, N. Y. : 
Hard, bright, No. i ; picked October 12, 1901, stored October 21 ; 
January 31, iqo2, mellow, no decay or scald; March 14, very ripe 
but still sound. 



Geo. T. Powell, Ghent, Columbia County, N. Y.: Bright, dark red, 
No. i; picked October 13, 1902, stored October 19; February i, 
1903, in prime commercial condition; March i, mellow, free from 
scald and decay. 

This variety reaches its commercial limit usually between January i 
and March i. 

New York State Experiment Station, Geneva, Ontario County, N. Y.: 
Small, hard, half colored ; picked September 27, 1902, stored October 
i; May i, 1903, semi-firm, some rot; commercial limit April i. 

Ozark Orchard Company, Goodman, McDonald County, Mo.: Very 
large, highly colored; picked October 6, 1902, stored October 11; 
March 11, 1903, overripe, 18 per cent decay; behavior similar in 
1901-2; commercial limit February i. 

G. R Spohr, Manhattan, Riley County, Kans. : Fruit large, well 
colored, firmer than Ozark Orchard stock; picked October i, 1901, 
stored October 6; March 20, 1902, firm, no decay or scald; would 
probably have kept well a month longer; received through Kansas 
Experiment Station. 

Virginia Agricultural Experiment Station, Blacksburg, Montgomery 
County, Va. : Well colored, firm, medium grade, considerable 
codling-moth injury; picked September 26, 1901, stored October 16; 
February i, 1902, firm, with" no decay or scald, after which the 
decay proceeded quite rapidly. 
Golden Russet (N. Y.). 

Maine Agricultural Experiment Station, Orono, Penobscot County, 
Me. : Bright, hard, well russeted. No. i ; picked October 7, 1901, 
stored October 24, 1901 ; commercial limit May i, 1902, when stock 
was hard, but mellowing began soon after. 

New York State Experiment Station, Geneva, Ontario County, N. Y. : 
Hard, greenish russet. No. i ; picked October 24, 1902, stored No- 
vember 15; May I, 1903, prime commercial condition, no decay; 
similar in 1901-2, but by June i the fruit was mellow and decay 
was setting in. 
Grimes. Synonym : Grimes Golden. 

W. S. Miller, Gerrardstown, Berkeley County, W. Va.: Bright, No. i; 
picked September 20, 1901, stored October 16; mellow when stored; 
began to deteriorate from decay after January i, 1902. 

New York State Experiment Station, Geneva, Ontario County, N. Y. : 
No. I, fair color; picked October 2, 1902, stored October 11 ; in 
good condition commercially till February i, 1903, when scald began 
to develop; May i, all scalded, semi-firm. 

Virginia Agricultural Experiment Station, Blacksburg, Montgomery 
County, Va. : No. 2; considerable codling-moth' injury; picked Sep- 
tember 26, 1901, stored October 16; limit December i, 1901, after 
which the fruit rotted badly; scald began to develop in March, 1902; 
probably injured by delay in storage. 
HuBBARDSTON. Synonyms : Hubbardston Nonesuch. Nonesuch. 

Z. A. Gilbert, Farmington, Franklin Co^ttty, Me. : Medium size, well 
colored, mixed grade; picking date^undetermined, stored November 
10, 1902; after December i, 1902, the flesh softened throughout; 
probably ripe when stored. 

G. G. Hitchings, South Onondaga, Onondaga County, N. Y. : Large, 
finely colored, considerable codling-moth injury; trees six years old; 
picked October 5. 1902, stored October 12; prime commercial condi- 
tion till February i, 1903, when it began to shrivel; April i, soft. 

Kansas Agricultural Experiment Station, Manhattan, Riley County, 
Kans.: Medium to small, pale greenish red; picked October 8, 1901. 


stored October 12; no softening and but little decay till April i, 
1902; fruit began to wilt after February i, 1902. 

Massachusetts Ajfricultural College Experiment Station, Amherst, 
Hampshire County, Mass.: Medium size, rather dull color; picked 
September 30, 1902, stored October 3; good commercial condition 
for barrel storage till January 15, 1903 ; for box storage till February 
I5> i903» after which the fruit mellowed and became mealy. 

New York State Experiment Station, Geneva, Ontario County, N. Y. : 
Small, hard, immature : picked October 4, 1902, stored October 1 1 ; 
prime condition May i, 1903. 

G. T. Powell, Ghent, Columbia County, N. Y. : Very large, overgrown, 
highly colored; picked October 4, 1902, stored October 9; firm until 
December i, 1902, after which the tlesh grew mealy; January 15, 
1903, all burst. 

The flesh of this variety usually becomes mealy when it passes ma- 

G. J. Dodd, Greenwood, Jackson County, Mo.: Large, well colored, 
firm. No. I ; picked September 22, 1902, stored September 24 ; com- 
mercial limit probably February i, 1903; March 11, 1903, 20 per cent 

G. G. Hitchings, South Onondaga, Onondaga County, N. Y. : Dark red, 
bright. No. i ; trees 6 years old ; picked October 5, 1901, stored Oc- 
tober 12] in fine condition for barrel storage till April i, 1902; 
in good condition for box storage till June i, 1902; no rot; held well 
for a long time after the fruit began to mellow. 

New York State Experiment Station, Geneva, Ontario County, N. Y. : 
Small, hard, considerably russeted; picked October 23, 1902, stored 
October 27; May i, 1903, hard, no rot, in prime commercial condi- 

G. T. Powell, Ghent, Columbia County, N. Y. : Medium sized, highly 
colored; picked October 16, 1902, stored October 19; in prime con- 
dition for barrel storage till March i, 1903, when fruit began to mel- 
low ; good condition for box storage till May i ; no rot or scald. 

F. H. Speakman, Neosho, Newton County, Mo. : Large, highly col- 
ored, No. i; picked September 25, 1901, stored October 16; commer- 
cial limit about February i, 1902; when inspected March 20 the 
fruit was mellow, with considerable decay; probably injured by de- 
layed storage. 

G. E. Spohr, Manhattan, Riley County, Kans. : Well colored, No. i ; 
picked October i, 1901, stored October 12; prime till February i, 
I9(^, when the fruit began to mellow ; received through Kansas Ex- 
periment Station. 

Lawver. Synonym: Delaware Red Winter. 

Near Kansas Agricultural Experiment Station, Manhattan, Riley 
County, Kans. : No. i, rather dull red ; picked October 18, 1901, 
stored October 21 ; good commercial condition March 20, 1902, and 
apparently would have kept well throughout storage season; re- 
ceived through Kansas Experiment Station. 

Massachusetts Agricultural College Experiment Station, Amherst, 
Hampshire County, Mass.: Small, dull red, very hard; picked Octo- 
ber II, 1902, stored October 15; May i, 1903, hard, no scald or decay. 

W. S. Miller, Gerrardstown, Berkeley County, W. Va. : Large, bright, 
dark red; picked October 11, 1901, stored October 16; good commer- 
cial condition till March 15, 1902, when some of the apples began 
to grow mealy; ripened unevenly; fruit overgrown. 

Virginia Agricultural Experiment Station, Blacksburg, Montgomery 
County, Va. : Small, No. 2; considerably injured by codling moth; 


picked September rj. 1901. stored October 16; May i, 1902, hard and 
in good condition ; a few decayed from bruising. 
McIntosh. Synonym: Mcintosh Red. 

G. G. Hitchings, South Onondaga, Onondaga County, N. Y. : Well 
colored, No. i; trees 12 years old; picked October 7, 1901, stored 
October 12; firm till January 15, 1902, after which it became mel- 
low ; behavior similar in i902-'o3. 

New York State Experiment Station, Geneva, Ontario County, N. Y. : 
Well colored, No. i : picked October 12, 1901, stored October 21 ; 
firm till January 15, 1902; good condition for box storage till March 
1, 1902; in I902-'o3 the fruit was firm a month longer. 
Missouri. Synonym: Missouri Pippin. 

F. H. Speakman, Neosho, Newton County, Mo. : Large, highly col- 
ored, No. i; picked October 20, 1901, stored October 30; March 20, 
1902, prime commercial condition, hard, no scald or decay; behavior 
similar in 1903; commercial limit probably April 15 to May i. 

Virginia Agricultural Experiment Station, Blacksburg, Montgomery 
County, Va. : No. 2, scabby, considerable "flyspeck" fungus and 
codling-moth injury; picked September 26, 1901, stored October 16; 
firm till March i, 1902, after which the fruit decayed badly. 

W. S. Miller, Gerrardstown, Berkeley County, W. Va. : Large, not 
well colored, immature; picked September 27, 1901, stored October 
18: semi-firm when stored, in good condition till March i, 1902, after 
which the fruit softened and scald appeared. The delay in storing 
undoubtedly shortened its storage period. 

Virginia Agricultural Experiment Station, Blacksburg, Montgomery 
County, Va. : No. 2, badly affected with codling moth, well colored ; 
picked September 26. 1901, stored October 16; after February i the 
fruit decayed considerably, though still firm ; scald appeared March 
I. 1902. 

This varietv is inclined to scald considerably after midwinter, unless 
it is highly colored. 
Northern Spy. 

F. L. Bradley, Barker, Niagara County, N. Y. : Poor grade, light col- 
ored; picked October 9, 1902, stored October 15; May i, 1903, firm 
and in good condition ; no rot or scald. 

A. A. Boggs, Waynesboro, Haywood County. N. C. : Large, dark red, 
fancy; picked September 25, 1902, stored September 30; firm until 
December i, 1902, after which it decayed and softened rapidly. 

G. G. Hitchmgs, South Onondaga, Onondaga County, N. Y. : Large, 
highly colored, fancy: trees 6 years old; picked October 22, 1901, 
stored October 26: May i, 1902, prime commercial condition, firm, 
no scald, slight rot. 

New York State Experiment Station. Geneva, Ontario County. N. Y. ; 
Well colored. No. i; picked October 12, 1901, stored October 21; 
May I, 1902. firm, good commercial condition; picked November 3, 
1902, stored November 15; light colored; in good condition till 
March i, 1903, after which the fruit decayed considerably. 

G. T. Powell, Ghent, Columbia County, N. Y. : Fancy, medium size, 
dark red; picked October 16, 1902, stored October 19; May i, 1903, 
hard, no rot or decay, and in prime condition. 

This variety is variable in its storage behavior. It is particularly sus- 
ceptible to decay from blue mold, especially if bruised or delayed in 
reaching storage. If well colored, picked, packed, and handled with 
great care, and stored soon after picking, it may be carried in storage 
as long as most winter varieties. 



G. G. Hitchings, South Onondaga, Onondaga County, N. Y. : Well 
colored, No. i ; trees 12 years old; picked September 25, 1902, stored 
September 29; May i, 1903, firm, no rot or scald; fruit picked in 
1901 kept in similar condition. 

Maine Agricultural Experiment Station, Orono. Penobscot County, 
Me. : Well colored, No. i ; picked October 7, 1902, stored October 
24; May I, 1903, firm, decay slight, no scald. 

Massachusetts Agricultural College Experiment Station, Amherst, 
Hampshire County, Mass. : Well colored, No. i ; picked October 
8, 1902, stored October 12 ; May i, 1903, firm, no scald or decay. 

W. S. Miller, Gerrardstown, Berkeley County, W. Va. : Well colored. 
No. i; picked October 8, 1901, stored October 18; May i, 1902, 
no scald or rot, firm. 

New York State Experiment Station, Geneva, Ontario County, N. Y. : 
Small, hard, and undercolored ; picked October 4, 1902, stored Octo- 
ber 11; May I, 1903, hard and green, no rot; fruit picked in 1901 
kept in similar condition. 
Ralls. Synonyms: Gcniton; Ralls Genet; Neverfail. 

H. M. Dunlap, Southern Illinois: Small, imperfect. No. 2; picked Oc- 
tober 9, 1901, stored October 15; January 17, 1902, firm, no decay 
or scald ; Slarch 18, considerable decay and some scald. 

W. S. Miller, Gerrardstown, Berkeley County, W. Va. : Bright, clean. 
No. i; picked October 12, 1901, stored October 18; May i, 1902, in 
prime condition, no rot, or decay. 
Red Canada. Synonyms: Canada Red; Steele's Red Winter. 

G. G. Hitchings, South Onondaga, Onondaga County, N. Y. : Dark 
red. No. i ; trees 6 years old ; dates of picking and storing undeter- 
mined; in prime commercial condition until April 15, 1902, after 
which date the fruit softened very quickly. 

New York State Experiment Station, Geneva. Ontario County, N. Y. : 
Immature, hard, No. i ; picked October 12, 1901, stored October 21 ; 
May I, 1902, firm, free from scald and decay. 
Rhode Island. 

F. L. Bradley. Barker, Niagara County, N. Y. : Firm, poorly graded ; 
picked September 27, 1002, stored October 3; in commercial condi- 
tion until March 15, 1903; May i, injured by scald and decay. 

J. E. Brown. Wilson, Niagara County, N. Y. : Not closely graded ; 
many .small and wormy fruits; dates of picking and storing unde- 
termined: March 13, 1902, considerable scald, decay slight. 

G. G. Hitchings, South Onondaga, Onondaga County, N. Y. : Bright, 
dark green, No. i; picked October 7, 1901, stored October 12; in 
prime commercial condition until March 15, 1902, when the fruit 
began to scald; May i, firm but badly scalded; fruit picked in 1902 
kept in similar condition. 

Z. A. Gilbert, Farmington, Franklin County, Me. : Small, green, fair. 
No. i; picking date undetermined, stored November 14, 1902; May 
I, 1903. in good commercial condition, free from scald and decay. 

W. T. Mann, Barker, Niagara County, N. Y. : Bright, large, No. i ; 
from heavy soil, very green ; from sandy soil, larger and yellower : 
picked October it. 1902, stored October 13; May i, 1903, in prime 
commercial condition, no scald or decay. 

Massachusetts Agricultural College Experiment Station, Amherst, 
Hampshire County, Mass. : Dull green. No. 2. covered with "fly- 
speck" fungus : picked October 8, 1902, stored October 12 ; in com- 
mercial condition until February i, 1903, when the fruit began to 
mellow and grow mealy, while very green outside. 

New York State Experiment Station, Geneva, Ontario County. N. Y. : 


Hard, sound, No. i; picked October 3, 1902, stored October 11; in 
good commercial condition until March 15, 1903, when the fruit 
began to discolor and soften ; fruit picked in 1901 kept in similar 
condition until the middle of March, 1902, except for the appear- 
ance of considerable scald. 

George T. Powell, Ghent, Columbia County, N. Y. : Bright, well col- 
ored. No. I : picked October 5, 1902, stored October 9; in good com- 
mercial condition until May i, 1903, when the scald began to ap- 

A. A. Boggs, Waynesville, Haywood County, N. C. : Large, dark 
red, No. i; picked September 15, 1902, stored September 26; March 
1, 1903, firm, no scald or rot. 

New York State Experiment Station, Geneva. Ontario County, N. Y. : 
Hard, light colored, No. i ; picked November 5, 1902, stored Novem- 
ber 15; March 14, 1903, firm and sound; fruit picked in 1901 in 
good commercial condition until May i, 1902. 

G. E. Spohr, Manhattan, Riley County, Kans. : Small, poorly colored ; 
dates of picking and storing undetermined ; March 20, 1902, consid- 
erably shriveled, but free from rot and scald. 


F. L. Bradley, Barker, Niagara County, N. Y. : Sound, No. i ; picked 
October i, 1902, stored October 3; in good commercial condition 
until May i, 1903, aside from slight shriveling. 

J. E. Brown, Wilson, Niagara County, N. Y. : No. i ; dates of picking 
and storing undetermined; May i, 1902, in prime commercial condi- 
tion, no shriveling, free from rot. 

Massachusetts Agricultural College Experiment Station, Amherst, 
Hampshire County, Mass. : Medium sized, green, not well russeted ; 
picked October 13. 1902, stored October 15; May i, 1903, in good 
commercial condition, no rot, some wilting. 

W. S. Miller, Gcrrardstown, Berkeley County, \V. Va. : No. i ; picked 
November 4, 1901, stored November 12; May i, 1902, in prime com- 
mercial condition, no wilting, free from rot. 

New York State Experiment Station, Geneva, Ontario County, N. Y. : 
No. 1; picked Octol^er 24, 1902, stored November 15; May i, 1903, 
firm, no decay; fruit picked in 1901 kept in similar condition. 

George T. Powell. Ghent, Columbia County, N. Y. : Large, bright, 
No. i; picked October 16, 1902, stored October 19; in prime com- 
mercial condition until May i, 1903. 

Virginia Agricultural Experiment Station, Blacksburg. Montgomery 
County. \'a. : Bright, No. i ; picked September 26, 1901, stored Oc- 
tober; May I, 1902, in prime commercial condition, no wilting or 

Maine Agricultural Experiment Station, Orono. Penobscot County. 
Me.*: Large, well colored, bright. No. i ; picked October 7, 1901, 
stored October 14: in prime commercial condition June 14, IQ02, 
when removed from storage: no scald or decay. 

W. S. Miller, Gerrardsiown. Berkeley County, \V. Va. : Medium sized, 
hard, fair colored. No. i ; picked October 2. 1901, stored October 8; 
scald appeared after April i, kx)2. but fruit remained hard through- 
out storage scT^OTi. 

New York State Experiment Station, Geneva. Ontario County. N. Y. : 
Hard, greenish red, \i». i : picked Octt ber 12. iQOi. stored October 
21 : iiard with uo scald (^r decay June 0. i<X)2. when removed from 


Sutton. Synonym: Suiton Beauty. 

Massachusetts Agricultural College Experiment Station, Amherst, 
Hampshire Count)', Mass. : Medium sized, bright, dark red, No. i ; 
picked October 8, 1902, stored October 12; firm for barrel storage 
till February i, 1903; semi-firm and in good condition for box storage 
till March 15, 1903, after which the fruit became mellow; no scald 
or rot. 

New York State Experiment Station, Geneva, Ontario County, N. Y. : 
Medium sized, well colored, but rather dull, No. i ; picked October 
21, 1902, stored October 27; firm for barrel storage till March 15, 
1903; in good condition for box storage till April 15, 1903. 

George T. Powell, Ghent, Columbia County, N. Y. : Fancy, large, 
bright, dark red, from young trees ; picked October 6, 1902, stored 
October 9: firm for barrel storage till February i, 1903; semi-firm 
and in good condition for box storage till March i, after which the 
flesh softened and became mealy; no rot or scald. 

This variety does not keep as long as Baldwin from the same or- 
Tompkins King. Synonym : King. 

F. L. Bradley, Barker, Niagara County, N. Y. : Well colored, No. i ; 
picked October 9, 1902, stored October 15; in good commercial con- 
dition until April 15, 1903, after which the fruit became mellow. 

J. E. Brown, Wilson, Niagara County, N. Y. : Well colored, No. i ; 
picked October 9, igoi, stored October 17; April 9, 1902, in good 
commercial condition, decay slight, no scald; commercial limit 
May I. 

G. G. Hitchings, South Onondaga, Onondaga Courtty, N. Y. : Large, 
dark red, No. i ; trees 13 years old; picked October 5, 1901, stored 
October 12; May 1, 1902, firm, no scald or rot; fruit picked in 1902 
did not keep later than April i, 1903. 

Massachusetts Agricultural College Experiment Station, Amherst, 
Hampshire County, Mass.: Medium sized, bright, half colored; 
picked September 30, 1902, stored October 3; May i, 1903, firm, no 
rot or scald. 

New York State Experiment Station, Geneva, Ontario County, N. Y. : 
Small, hard, and green: picked September 23, 1902, stored Sep- 
tember 27; May I, 1903, green and hard, no decay or scald; fruit 
picked in 1901 kept in sound condition until May i, 1902. 

George T. Powell, Ghent, Columbia County, N. Y. : Very large, well 
colored, No. i, from young, rank-growing trees; picked October 4, 
1902, stored October 9; held well until January i, 1903, when the 
fruit began to soften and become mealy. 

G. G. Hitchings, South Onondaga, Onondaga County, N. Y. : Fair. 
No. i; picked October i, 1902, stored October 4; began scalding 
February i, 1903, and by March 15 over 50 per cent of the fruit was 
scalded ; commercial limit about February i on account of scald. 

New York State Experiment Station, Geneva, Ontario County, N. Y. : 
Hard, well colored. No. i ; picked November 5, 1902, stored Novem- 
ber 15; March 14, firm, no decay or scald; May i, 1903, soft, con- 
siderable decay, no scald. 

George T. Powell, Ghent, Columbia County, N. Y. : Half red. No. i ; 
picked October 16, ic)02, stored October 19: held in prime condition 
until April i, 1903; no rot or scald; after February i the light side 
of the fruit would scald badly within forty-eight hours after removal 
from storage. 

This variety unless highly colored is one of the worst to scald after 


Willow. Synonym : IViliowtwig. 

H. M. Dunlap, Savoy, 111. : No. i ; picked October lo, igoi, stored 
October 15; March 18, 1902, firm, slightly injured by scald and rot. 
Virginia Agricultural Experiment Station, Blacksburg, Montgomery 
County, Va. : No. 2 ; cloudy and wormy ; picked September 20, 1901 ; 
date of storing undetermined; May i, 1902, commencing to shrivel, 
no scald, decay slight. 


S. H. Derby, Woodside, Kent County, Del. : Hard, light red, No. i ; 
picked September 29, 1902, stored September 31 ; May i, 1903, hard, 
no scald or rot; in prime condition to carry lor many weeks. 

G. J. Dodd, Greenwood, Jackson County, Mo. : Well colored. No. i ; 
picked October i, 1901, stored October 4; March 10, 1903, in prime 
commercial condition, no rot, scald very slight ; commercial limit, 
on account of scald, March 15. 

H. M. Dunlan. Savoy, Champaign County, 111. : No. i ; slightly 
wormy; picked October 23, 1901, stored October 28; January 17, 

1902, sound and in good commercial condition; March 18, firm, no 
scald, decay slight ; fruit picked two weeks earlier and lighter in 
color was one-third scalded. 

G. G. Hitchings, South Onondaga, Onondaga County, N. Y. : Small, 
hard, dark red; trees six years old; picked October 13, 1902, stored 
October 16; kept well until March i, 1903, when scald began to de- 
velop. Fruit picked in 1901 kept in similar condition. Hard 
throughout storage season. 

Near Kansas Agricultural College, Manhattan, Riley County, Kans. : 
Hard, small, poorly colored; picked October 4, 1901. stored October 
10; March 20, 1902, hard, no rot or scald; commercial limit proba- 
bly April 15. 

S. L. Lupton, Winchester, Frederick County. Va. : Fair, No. i ; color 
fair; somewhat cloudy and wormy; picked October 18, 1901, stored 
October 22 ; March 27, 1902, firm, decay slight, one-third scalded. 

Ozark Orchard Company. Goodman, McDonald County, Mo. : Well 
colored, No. i ; picked October 8, IQ02, stored October 13 ; March 10, 

1903, firm, no scald, 20 per cent of rot; commercial limit February i. 
New York State Experiment Station, Geneva, Ontario County, N. Y. : 

Hard, small, light colored ; picked October 12, 1901, stored October 
21 ; March 14, 1902, firm, no decay or scald ; April 30, about 75 per 
cent of scald, no decay, hard. 
Virginia Agricultural Experiment Station, Blacksburg, Montgomery 
County, Va. : Medium sized, fair. No. i ; picked September 30, 1901, 
stored October 17 ; May i, 1902, firm, no scald, very slight decay, 
and wilting. 
Yellow Bellflower. Synonym : BellHo'n^r. 

F. L. Bradley, Barker, Niagara County, N. Y. : No. 2 grade, scabby 
and russeted ; picked October 9, 1902, .stored October 15; May i, 
1903, semi-firm and free from scald and decay. 

G. T. Powell. Ghent, Columbia County, N. Y. : Highlv colored. No. 
i: picked October 9. 1902, stored October 13; April i, 1903, begin- 
ning to mellow, no scald or rot. 

Yellow Newtown. Synonyms: Albemarle: Newtown Pippin; Yellow 
Newtown Pippin. 
S. L. Lupton. Winchester. Frederick County. Va. : Medium sized, 
well colored, wormy; picked October 7, 1901, stored October 10; 
May I. 1902, firm, decay and scald slight; commercial limit April i. 
W. S. Miller, Gerrardstown, Berkeley County, W. Va. : Bright, No. 
i: picked October 10. 1901, stored October 18; June 14, 1902, in 
prime commercial condition, no scald or decay. 


Virginia Agricultural Experiment Station, Blacksburg, Montgomery 
County, Va. : Somewhat wormy; picked September 27, 1901, stored 
October 17; June 14, 1902, firm, color and quality good; decay and 
scald slight; commercial limit May 15. 
York Imperial. Synonym: Johnson's Fine Winter. 

A. A. Boggs, Waynesville, Haywood County, N. C. : Hard, bright, 
half colored, No. i ; picked September 18, 1902, stored September 25 ; 
May I, 1903, firm, no scald or decay. 

S. L. Lupton, Winchester, Frederick County, Va. ; Medium grade, 
greenish red, considerable codling moth; picked October 4, 1901, 
stored October 12; scalded badly after January i, 1902; fruit picked 
October 23, dark red, began to scald after February i, but did not 
scald as badly as the early picked fruit; the commercial limit of the 
dark fruit was six weeks longer. 

New York btate Experiment Station, Geneva, Ontario County, N. Y, : 
Medium to small, light colored, very hard; picked October 1-12, 

1901, stored October 21 ; began to scald February 15, 1902, and a 
month later three-fourths of the fruit was lightly scalded on the 
green side; remained firm throughout season; commercial limit 
February 15 to March 15. 

Ozark Orchard Company, Goodman, McDonald County, Mo. : Large, 
well colored. No. i ; picked October 8, 1902, stored October 13 ; 
March 10, 1903, overripe, somewhat shriveled, one-third of the fruit 
decayed, no scald; commercial limit January 15. 

Virginia Agricultural Experiment Station, Blacksburg, Montgomery 
County, Va. : Bright, well colored. No. i ; picked September 26, 1901, 
stored October 17; January 24, 1902. firm, no decay, one-third of the 
fruit slightly scalded; commercial limit January i. 

F. Wellhouse, Tonganoxie, Leavenworth County, Knns. : Two-thirds 
colored; picked October 8, 1901, stored October 12; March 20, 

1902, slightly wilted, some decay, one-fourth of the fruit scalded; 
commercial limit February 15. 


An apple should usually be fully grown and highly colored 
when picked to give it the best keeping and commercial quali- 
ties. When harvested in that condition it is less liable to scald, 
is of better quality, more attractive in appearance and is w-orth 
more money than when it is picked in greener condition. 

An exception to the statement appears to exist in the case 
of certain varieties when borne on rapidly growing young trees. 
Such fruit is likely to be overgrown, and under these conditions 
the apples may need picking before they reach their highest 
color and fullest development. 

Uniform color may be secured by pruning to let the sunlight 
into the tree, by cultural conditions that check the growth of 
the tree early in the fall, and by picking over the trees several 
times, taking the apples in each picking that have attained the 
desired degree of color and size. 


Apples should be stored as quickly as possible after picking. 
The fruit ripens rapidly after it is picked, especially if the 
weather is hot. The ripening which takes place between the 
time of picking and storage shortens the life of the fruit in the 
storage house. The fruit rots multiply rapidly if storage is 
delayed and the fruit becomes heated. If the weather is cool 
enough to prevent after-ripening, a delay in the storage of the 
fruit may not be injurious to its keeping quality. 

A temperature of 31° to 32° F. retards the ripening processes 
more than a higher temperature. This temperature favors the 
fruit in other respects. 

A fruit wrapper retards the ripening of the fruit; it pre- 
serves its bright color, checks transpiration and lessens wilting, 
protects the apple from bruising, and prevents the spread of 
fungous spores from decayed to perfect fruit. In commercial 
practice the use of the wrapper may be advisable on the finest 
grades of fruit that are placed on the market in small packages. 

Apples that are to be stored for any length of time should 
be placed in closed packages. Fruit in ventilated packages is 
likely to be injured by wilting. Delicate fruit and fruit on which 
the ripening processes need to be quickly checked should be 
stored in the smallest practicable commercial package. The 
fruit cools more rapidly in small packages. 

Apples should be in a firm condition when taken from 
storage, and kept in a low temperature after removal. A high 
temperature hastens decomposition and develops scald. 

The best fruit keeps best in storage. When the crop is 
light it may pay to store fruit of inferior grade, but in this case 
the grades should be established when the fruit is picked. The 
bruising of the fruit leads to premature decay. 

The scald is probably caused by a ferment or enzyme which 
works most rapidly in a high temperature. Fruit picked before 
it is mature is more susceptible than highly colored, well-devel- 
oped fruit. 

After the fruit is picked its susceptibility to scald increases 
as the ripening progresses. 

The ripening that takes place between the picking of the 
fruit and its storage makes it more susceptible to scald, and de- 
lay in storing the fruit in hot weather is particularly injurious. 


The fruit scalds least in a low temperature. On removal 
from storage late in the season the scald develops quickly, es- 
pecially when the temperature is high. 

It does not appear practicable to treat the fruit with gases 
or other substances to prevent the scald. 

From the practical standpoint the scald may be prevented 
to the greatest extent by producing highly colored, well-devel- 
oped fruit, by storing it as soon as it is picked in a temperature 
of 31° to 32° F., by removing it from storage while it is still 
free from scald, and by holding it after removal in the coolest 
possible temperature. 

A variety may differ in its keeping quality when grown in 
different parts of the country. It may vary when grown in the 
same locality under different cultural conditions. The character 
of the soil, the age of the trees, the care of the orchard — all of 
these factors modify the growth of the tree and fruit and may 
affect the keeping quality of the apples. The character of the 
season also modifies the keeping power of the fruit. 




Before the advent of the cold-storage business the supply of 
summer pears frequently exceeded the demand. This condition 
of the markets, which were demoralized in hot, humid seasons, 
pertained especially to the early varieties, Hke the Bartlett, which 
ripen in hot weather and need to be sold in a short time to pre- 
vent heavy losses from rapid decay. The introduction of the 
refrigerator car and of the cold storage warehouse, together with 
the rapid growth of the canning industry, has done much to im- 
prove the pear situation by artificially establishing a well regulated 
and more uniform supply of fruit throughout a longer period of 
time. The pear acreage of the country has more than doubled 
within a decade, and is enlarging the relative importance of 
cold storage to the pear-growing business, though a large part 
of the increase, especially in California, along the Atlantic coast 
from New Jersey southward, in Texas, and in the central west, 
is primarily related to the canning industry. 

Pear storage has developed most largely in the east. In 
New York and Jersey City from 60.000 to 100,000 bushels of 
summer pears, 30,000 to 60.000 bushels of later varieties, and 
many cars of California pears are stored annually. In Boston, 
since 1895 there have been stored each year from 5,000 to 15,000 
bushels of early pears, principally Bartlett, and from 7,000 to 
20,000 bushels of later varieties, such as Anjou, Bosc, Angouleme 
(Duchess) y Seckel, and Sheldon. In Buffalo 10,000 bushels 
are sometimes stored in a single season, and in Philadelphia from 
30,000 to 35,000 bushels. While there are no accurate statistics 
available and the quantity fluctuates from year to year, it is 

♦Extracts from Bulletin No. 40, Bureau of Plant Industry. United States Depart- 
ment of Agriculture, by G. Harold Powell, Assistant Pomologist in charge of Field 
Investigations, and S. H. Fulton, Assistant in Pomology. 


probable that as many as 3CX),ooo bushels are stored in a single 
year throughout the country at large. 

There are many practical difficulties in pear storage. The 
early-ripening varieties which mature in hot weather, like the 
Bartlett, often "slump" before they reach the storage house, or 
are in soft condition, especially if they have been delayed in 
ordinary freight cars in transit. They may afterwards decay 
badly in storage, break down quickly on removal, or lose their 
delicate flavor and aroma. When stored in a large package like 
the barrel, the fruit, especially of the early varieties, often softens 
in the center of the package, while the outside layers remain 
firm and green. Frequently no two shipments from the same 
orchard act alike, even when stored in adjoining packages in 
the same room, and the warehouseman and the owner, not always 
knowing the history of the fruit, are at a loss to understand the 
difficulty. It has been the aim in the fruit-storage investigations 
of the Department of Agriculture to determine as far as possible 
the reasons for some of these storage troubles, and to point out 
the relation of the results to* a more rational storage business. 


The investigations in pear storage were of a preliminary na- 
ture only. The experiments undertaken have been planned with 
a view to determining the influence in the storage room of 
various temperatures, of the character of the storage package, 
of a fruit wrapper, of the degree of maturity of the fruit when 
picked, and of other factors in relation to the ripening processes 
in the storage house, and also to ascertain the behavior of the 
fruit and its value to the consumer when placed on the market. 

The Bartlett and Kieflfer pears principally were used in 
the experiments, but several other kinds were under limited 
observation. The Bartlett represents the delicate-fleshed, tender 
pears, ripening in hot weather, which are withdrawn from stor- 
age before the weather becomes cool. The Kieflfer, on the other 
hand, is a coarse, hard pear, ripening later in the fall in cooler 
weather, and in which the normal ripening processes are slower. 
It is a longer keeper, and like other fall varieties is withdrawn 
in cool weather. 

The Bartlett experiments extended through the season of 
1902. The fruit was grown by Mr. F. L. Bradley, Barker, N. Y., 


in a twelve-year-old orchard on a sandy loam, with a clay subsoil. 
The orchard is a half mile from Lake Ontario and is 50 feet 
above the level of the lake. The fruit, which was full grown, 
but green, was picked early in September, and was packed in 
tight and ventilated barrels, in 40-pound closed boxes, and in slat 
bushel crates. Part of the fruit in each lot was wrapped in un- 
printed news paper, and an equal amount was left unwrapped. 
Part was forwarded at once by trolley line to the warehouse of 
the Buffalo Cold Storage Company at Buffalo, N. Y., and a 
similar quantity was held four days before being stored. The 
fruit reached the storage house within ten hours after leaving 
the orchard. 

The Kieffer experiments have extended over two years. In 
1901 the fruit was grown by Mr. M. B. Waite, Woodwardsville, 
Md., in a Norfolk sandy soil, on rapidly growing five-year-old 
trees, from which the fruit was large, coarse, and of poor quality. 
It was stored in the cold storage department of the Center Market 
at Washington, D. C. In 1902 the fruit with which the experi- 
ments were made was grown by Mr. S. H. Derby, Woodside, 
Del, on heavy-bearing ten-year-old trees on sandy soil with a 
clay subsoil. The fruit was smaller, of finer texture, and of 
somewhat better quality than that used the previous year. It was 
stored in the cold storage department of the Reading Terminal 
Market in Philadelphia, Pa. 

The Kieffers were picked at three degrees of maturity: 
First, when two-thirds grown, or before the fruit is usually 
picked; second, ten days later, or about the time that Kieffers 
are commonly picked, and third, ten days later, when the fruit 
was fully grown and still green, but showing a yellowish tinge 
around the calyx. In each picking, part of the fruit was shipped 
to storage and was placed in rooms with a temperature of 36° 
and 32° F. within forty-eight hours. Equal quantities stored in 
each temperature were wrapped in parchment paper, in unprinted 
news paper, and were left unwrapped. A duplicate lot of fruit 
remained in a common storage house ten days in open boxes, 
when it was packed in a similar manner and sent to storage. 
This fruit colored considerably during the interval, but was still 
hard and apparently in good physical condition on entering the 
storage house. The pears were stored in 40-pound closed boxes 


and in five-eighths bushel peach baskets. One hundred and 
fifty bushels were used in the experiments. 


The experiments with the Kieffer pear show that under con- 
ditions similar to those in Delaware and eastern Maryland this 
variety may safely be picked from the same orchard during a 
period of at least three weeks, or when from two-thirds grown 
to full size, and that the fruit in all cases may be stored success- 
fully until the holidays, or much longer if there is still a demand 
for it. It is absolutely essential that the fruit be handled with the 
greatest care, that it be sent at once to storage after picking, 
that it be packed carefully to prevent bruising (preferably in 
small packages, like a bushel box), and that it be stored in a 
temperature not above 32° F. if it is desired to hold it for any 
length of time. If stored by the middle of October, the fruit, by 
the latter part of December, will take on a rich, yellow color 
when kept in a temperature of 32° F., and earlier if a higher 
temperature is used. The fruit may be withdrawn during the 
holidays, and will stand up, i. e., continue in good condition, for 
ten days or longer if the weather is cool, and will retain its 
normal quality if the rooms have been properly managed. While 
the later picked fully grown pears keep well, they are already 
inferior in quality at the picking time, as the flesh around the 
center is filled with woody cells, making it of less value either 
for eating in a fresh state or for culinary purposes. These coarse 
cells in the Kieffer and some other late varieties do not develop 
in the early picked fruit to so large an extent. Pears of all 
kinds need to be picked before they reach maturity and to be 
ripened in a cool temperature if the best texture and flavor are 
to be developed. It is a matter of practical judgment to deter- 
mine the proper picking season, but for cold storage or other 
purposes the stem should at least cleave easily from the tree 
before the fruit is ready to pick. Many trees bear fruit differing 
widely in the degree of maturity at the same time, and in such 
cases uniformity in the crop can be attained only when the or- 
chard is picked several times, the properly mature specimens be- 
ing selected in each successive picking. This practice not only 
secures more uniformity in ripeness, but the fruit is more even 


and the average size is larger than when all the pears are picked 
at the same time. 


Pears ripen much more rapidly after they are picked than 
they do in a similar temperature while hanging on the tree. The 
rapidity of ripening varies with the character of the variety, the 
maturity of the fruit when picked, the temperature in which it 
is placed, and the conditions under which it has been grown. 
If the fruit is left in the orchard in warm weather in piles or in 
packages, if it is delayed in hot cars or on a railroad siding in 
transit, or if it is put in packages which retain the heat for a long 
time, it continues to ripen and is considerably nearer the end of 
its life history when it reaches the storage house than would 
otherwise be the case. The influence of delay in reaching the 
storage house will therefore vary with the season, with the 
variety, and with the conditions surrounding the fruit at this time. 
A delay of a few days with the quick-ripening Bartlett in sultry 
August weather might cause the fruit to soften or even decay 
before it reached the storage house, though a similar delay in 
clear, cooler weather would be less hurtful. A delay of a like 
period in storing the slower ripening Kieffer would be less in- 
jurious in cool October weather, though the Kieffer pear, es- 
pecially from young trees, can sometimes be ruined commercially 
by not storing it at once after picking. 

From the experiments with the Bartlett and the Kieffer 
pears, from which these general introductory remarks are de- 
duced, it was found that the Bartlett, if properly packed, kept in 
prime condition in cold storage for six weeks, provided it was 
stored within forty-eight hours after picking in a temperature of 
32° F. ; but that if the fruit did not reach the storage room until 
four days after it was picked there was a loss of 20 to 30 per 
cent from softening and decay under exactly similar storage 

The Kieffers stored within forty-eight hours in a tempera- 
ture of 32° F. have kept in perfect condition until late winter, 
although there is little commercial demand for them after the 
Holidays. The fruit grown by Mr. Waite on young trees in 
1901, which was still hard and greenish-yellow when stored ten 
days after picking, began to discolor and soften at the core in a 





few days after entering the storage room, though the outside of 
the pears appeared perfectly normal. After forty to fifty days 
the flesh was nearly all discolored and softened, and the skin 
had turned brown. The fruit from the older trees on the Derby 
farm in 1902, which was smaller and finer in texture, appeared 
to ripen as much as the Waite pears during the ten days' delay. 
This fruit, however, did not discolor at the core and decay from 
the inside outward, but continued to ripen and soften in the 
storage house and was injured at least 50 per cent in its com- 
mercial value by the delay. Fig. i shows the condition of the 
Kieffer pears stored in a temperature of 32° F. as soon as picked 
and withdrawn in March. Under these conditions the fruit kept 
well until late in the spring. Fig 2 shows the condition of fruit 
picked at the same time and stored in the same temperature ten 
days after picking, when withdrawn in January. The delay in 
storage caused the fruit to decay from the core outward. 

Fig. 3 shows the influence of immediate and delayed stor- 
age on Maryland Kieflfer pears. The fruit in the box at the 
right represents the average condition of pears picked October 
21, stored October 22, and withdrawn March 3. Storage tem- 
perature 32° F. The fruit was wrapped in parchment paper. 
It was in prime commercial condition when withdrawn from 
storage. The fruit in the box at the left represents the average 
condition of pears picked from the same trees at the same time. 
It was stored in the same temperature ten days later and with- 
drawn March 3. All of the fruit had decayed. 

The results of the experiments point out clearly the injury 
that may occur by delaying the storage of the fruit after it is 
picked, and emphasize the importance of a quick transfer from 
the orchard to the storage house. If cars are not available for 
transportation and the fruit can not be kept in a cool place, it is 
safer on the trees so far as its ultimate keeping is concerned. 
It is advisable to forward to storage the delicate quick-ripening 
varieties, like the Bartlett, in refrigerator cars. The common 
closed freight car in warm weather soon becomes a sweat box 
and ripens the fruit with unusual rapidity. The results show 
clearly that the storage house may be responsible in no way for 
the entire deterioration or even for a large part of the deteriora- 
tion that may take place while the fruit is in storage, and that the 





different behavior of two lots from the same orchard may often 
be due to the conditions that exist during the period that elapsed 
between the time of picking and of storage. 


There is no uniformity in practice in the temperatures in 
which pears are stored. Formerly a temperature of 36° to 40° 
F. was considered most desirable, as a lower temperature was 
supposed to discolor the flesh and to injure the quality of the 
fruit. The pears were also believed to deteriorate much more 


rapidly when removed to a warmer air. In recent years a num- 
ber of storage houses have carried the fruit at the standard apple 
temperatures, i. e., from 30° to 32° F. Large quantities of Bart- 
lett, Angouleme. and Kieffer pears have been stored in 32° and 
36° F. in the experiments of the Department. The fruit of all 
varieties has kept longer in the lower temperature and the flesh 
has retained its commercial qualities longer after removal from 
the storage house. Bartlett pears were in prime commercial 
condition four to five weeks longer. Angouleme two months 
longer, and Kieffer three months longer in a temperature of 32° 
F. Figs. I and 5 show the condition of Kieffer pears in March, 



1902, in 32° and 36° F., the two lots having received similar 
treatment in all respects except in storage temperatures. The 
fruit held at 36° F. did not keep well after December i. 

Fig. 4 also shows the influence of 36° and 32° F. storage 
temperature on the keeping of Kieffer pears. The fruit in both 
packages was picked October 21, and stored October 22. The 
package at the left represents the average condition of the fruit 
when withdrawn March 3 from a temperature of 36° F. All 
of the pears were soft and discolored, and some of them decayed. 
The fruit in the package at the right, kept in a temperature of 



32° F., was bright yellow, firm, and in prime commercial con- 

In the higher temperature the fruit ripens more rapidly, 
which may be an advantage when it is desirable to color the fruit 
before it leaves storage ; but the fruit in that condition is nearer 
the end of its life history and breaks down more quickly on 
removal to a warm atmosphere. 

There is a much wider variation in the behavior of pears 
that have been delayed in storage or that are overripe when they 


enter the storage room at 32° and 36° F. than in pears stored at 
once in these temperatures. In the higher temperature the fruit 
that has been improperly handled ripens and deteriorates more 
quickly. The lower temperature not only keeps the fruit longer 
when it is stored at once, but it is even more essential in pre- 
venting rapid deterioration in fruit that has been improperly 


Pears are commercially stored in closed barrels, in ventilated 
barrels, in tight boxes holding a bushel or less, and in various 
kinds of ventilated crates. The character of the package exerts 
an important influence on the ripening of the fruit and on its 
behavior in other respects, both before it enters the storage house 
and after it is stored, though this fact is not generally recog- 
nized by fruit handlers or by warehousemen. The influence of 
the package on the ripening processes appears to be related pri- 
marily to tlie ease with which the heat is radiated from its con- 
tents. The greater the bulk of fruit within a package and the 
more the air of the storage room is excluded from it the longer 
the heat is retained. Quick-ripening fruits, like the Bartlett 
pear, that enter the storage room in a hot condition in large, 
closed packages, may continue to ripen considerably before the 
fruit cools down, and the ripening will be most pronounced in 
the center of the package, where the heat is retained longest. The 
influence of the package, therefore, will be most marked at the 
time during which the fruit is exposed to the hottest weather 
and on those fruits that ripen most quickly. 

In the experiments of the Department of Agriculture the 
Bartlett pears were stored in tight and in ventilated barrels, in 
closed 40-pound boxes, and in slat bushel crates. After three 
weeks in the storage house the fruit that was stored in barrels 
soon after picking in a temperature of 32° F. was yellow in the 
center of the package, while the outside layers were firm and 
green. Fig. 6 shows the average condition of the fruit in these 
two positions one week after storing. The upper specimen shows 
the condition of the fruit in center of a barrel. In this position 




the fruit cools more slowly than that near the staves or ends 
and it therefore ripens considerably before the temperature is 
reduced. The lower specimen shows the condition of the pears 
at top and bottom and next to the staves of the same barrel. 
In these positions the fruit cools quickly and the ripening proc- 
esses are retarded. For quick ripening fruits that are handled 
in hot weather small packages are preferable. After five weeks 
in storage the fruit in the center of the barrel was soft and of 
no commercial value, while the outside layers were still in good 
condition. The difference was still greater in a temperature of 
36° F., and was more marked in both temperatures in fruit that 
was delayed in reaching the storage house. 

In both the closed 40-pound boxes and the slat crates the 
fruit was even greener in average condition than the outside 
layers in the barrels, and it was uniformly firm throughout the 
entire package. 

There was apparently no difference between the fruit in 
the commercial ventilated pear barrel and the common tight pear 

With the Kieffer, which enters the storage room in a cooler 
condition and which ripens more slowly, a comparison has been 
made (in 1902) between the closed 40-pound box and the barrel, 
and while the difference has been less marked the fruit has kept 
distinctly better in the smaller package. The fruit in barrels was 
the property of Mr. M, B. Waite, and was under observation by 
the Department through his courtesy. 

There is a wide difference of opinion concerning the value 
of ventilated in comparison with tight packages for storage pur- 
poses. No dogmatic statements can be made that will not be 
subject to many exceptions. The chief advantage of a ventilated 
package for storage appears to lie in the greater rapidity with 
which the fruit cools, and the quickness with which this result 
is attained depends upon the temperature of the fruit, its bulk, 
the temperature of the room, and the openness of the package. 
The open-slat bushel crate, often used for storing Bartlett pears, 
with which rapid cooling is of fundamental importance, may be 
of much less value in storing later fruits that are cooler and 
which ripen more slowly, and it may be of even less importance in 
Bartletts in cool seasons. 





The ordinary ventilated pear barrel does not appear to have 
sufficient ventilation to cool the large bulk of fruit quickly. 

The open package has several disadvantages. If the fruit 
is to remain in storage for any length of time its exposure to the 
air will be followed by wilting, which, in fruits held until late 
winter or spring, may cause serious commercial injury. The 
ventilated package, especially if made of slats, needs to be han- 
dled with the utmost care to prevent the discoloration of the fruit 
due to bruising where it comes in contact with the edges of the 

There was little difference in the behavior of the Bartletts 
in the closed 40-pound boxes and the slat crates at the end of five 
weeks, and it would appear that a package of this size, even 
though closed, radiates the heat with sufficient rapidity to quickly 
check the ripening. Therefore the grower who uses the 40- 
pound or the bushel pear box for commercial purposes can store 
the fruit safely in this package, but if the barrel is used as the sell- 
ing package, and the weather is hot, it is a better plan to store 
the fruit in smaller packages, from which it may be repacked in 
barrels at the end of the storage season. While this practice is 
followed in several storage houses, it is not to be encour- 
aged, as the rehandling of the fruit is a disadvantage. Rather 
the use of the pear box should be encouraged as a more desirable 
package, both for storage and for commercial purposes. 

The fruit package question, as it relates to the storage house, 
may be summed up by stating that fruits like the Bartlett pear 
and others that ripen quickly and in hot weather may be expected 
to give best results when stored in small packages. If the storage 
season does not extend beyond early winter, an open package 
may be of additional value, though not necessary if the package 
is small. But fruits like the winter apples and late pears, which 
ripen in the fall in cool weather and remain in storage for a long 
period, should be stored in closed packages to prevent wilting. 
In such cases the disadvantages of a large package, like a barrel, 
are not likely to be serious. 


The life of a fruit in cold-storage is prolonged by the use of a 
fruit wrapper, and the advantage of the wrapper is more marked 


as the season progresses. In Figs. 7 and 8 are shown the aver- 
age quantity of sound specimens of Kieffer pears in unprinted 
news paper and in parchment wrappers in comparison with the 
quantity of commercial unwrapped pears in boxes in January, 
the fruit having been picked October 21 and placed in storage 
on the following day in a temperature of 32° F. Nearly 50 per 
cent of the unwrapped fruit (see Fig. 7) had decayed at that 
time, while that in unprinted newspaper and in parchment 
wrappers (see Fig. 8) kept in perfect condition. Early in the 
season the influence of the wrapper is not so important, but if 
the fruit is to be stored until late spring the wrapper keeps the 
fruit firmer and brighter. It prevents the spread of fungus 


spores from one fruit to another and thereby reduces the amount 
of decay. It checks the accumulation of mold on the stem and 
calyx in long-term storage fruits, and in light colored fruits it 
prevents bruising and the discoloration that usually follows. 

Careful comparisons were made of the efficiency of tissue, 
parchment, unprinted news paper, and waxed papers, and but 
little practical difference was observed, except that a large amount 
of mold had developed on the parchment wrappers in a tempera- 
ture of 36° F. A double wrapper proved more efficient for long 
keeping than a single one, and a satisfactory combination consists 
of an absorbent, unprinted news paper next to the fruit, with a 
more impervious paraffin wTapper outside. 


The chief advantage of the wrapper for the Bartlett pear, 
which is usually stored for a short time only, lies in the mechan- 
ical protection to the fruit rather than in its efficiency in pro- 
longing its season. Its use for this purpose is advisable if the 


fruit is of superior grade and designed for a first-class trade. 
For the late varieties the wrapper presents the same advantages, 
and has an additional value in increasing the commercial life of 
the fruit. It is especially efficient, if the package is not tight, 
in lessening the wilting. 




There is a general impression that cold storage injures the 
delicate aroma and characteristic flavors of fruits. In this publi- 
cation the most general statements only can be made concerning 
it, as the subject is of a most complicated nature, not well under- 
stood, and involving a consideration of the biological and chem- 
ical processes within the fruit and of their relation to the changes 
in or to the development of the aromatic oils, ethers, acids, or 
other products which give the fruit its individuality of flavor. 

It is not true that all cold storage fruits are poor in quality. 
On the contrary, if the storage house is properly managed the 
most deHcate aromas and flavors of many fruits are developed 
and retained for a long time. The quality of the late fall and 
winter apples ripened in the cold storage house is equal to that 
of the same varieties ripened out of storage, and the late pears 
usually surpass in quality the same varieties ripened in common 

The summer fruits, like the peach, the Bartlett pear, and 
the early apples, lose their quality very easily, and in an improper- 
ly managed storage house may have their flavors wholly de- 
stroyed. Even in a room in which the air is kept pure the flavor 
of the peach seems to be lost after two weeks or more, while the 
fruit is still firm, much as the violet and some other flowers 
exhale most of their aromatic properties before they begin to wilt. 

It is probable that much of the loss in quality may be at- 
tributed to overmaturity, brought about by holding the fruit in 
storage beyond its maximum time; but it should be remembered 
that the same change takes place in fruits that are not ripened in 
cold storage, the aroma and fine flavor often disappearing before 
the fruit begins to deteriorate materially in texture or appear- 

On the other hand, it is certain that the quality of stored 
fruits may be injuriously affected by improper handling or by the 
faulty management of the storage rooms. Respiration goes on 
rapidly when the fruit is warm. If placed in an improperly ven- 
tilated storage room, in which odors are arising from other 
products stored in the same compartment or in the same cycle 
of refrigeration, the warm fruit may absorb these gases and 


become tainted by them, while the same fruit, if cool when it 
enters the storage room, will breathe much less actively, and 
there will be less danger of injury to the quality, even though the 
air is not perfectly sweet; The atmosphere of the rooms, in 
which citrus fruits or vegetables of various kinds — such as cab- 
bage, onions, and celery — are stored, is often charged with the 
odors arising from these products, if the ventilation is not thor- 
ough. In small houses, in which a single room can not be used 
for each product, fruits are often stored together during the 
summer months, and at this period the storage air is in greater 
danger of vitiation, since it is more difficult to provide proper 

The summer fruits, therefore, being generally hot when 
placed in the storage room, are in condition to absorb the odors 
which are likely to affect the rooms during the warm season, and 
as the biological and chemical processes are normally more active 
in the case of such fruit than in fruits maturing later, the flavors 
deteriorate more quickly, even in well-ventilated rooms. The 
fruits that are picked in cool weather and enter the storage rooms 
in a cooler and less active condition are not in the same danger 
of contamination. 

From the practical standpoint it may be pointed out that 
summer fruits should be stored in rooms in which the air is 
sweet and pure. They should not be stored with products which 
exhale strong aromas, and the danger of contamination is less- 
ened if the fruit can be cooled down in a pure room before it is 
placed with other products in the permanent compartment pro- 
vided for it. For the same reason the winter fruits should be 
stored in rooms in which the air is kept pure, and preferably in 
compartments assigned to a single fruit. 

The experiments furnished no evidence that the quality de- 
teriorates more rapidly as the temperature is lowered. On the 
contrary, all of the experience so far indicates that the delicate 
flavors of the pear, apple, and peach are retained longer in a 
temperature that approaches the freezing point than in any 
higher temperature. 


There is a general impression that cold storage fruit de- 
teriorates quickly after removal from the warehouse. This 


opinion is based on the experience of the fruit handler and the 
consumer, and in many cases is well founded, but this rule is not 
applicable to all fruits in all seasons. The rapidity of deteriora- 
tion depends principally on the nature of the fruit, on its degree 
of maturity when it leaves the warehouse, and on the temperature 
into which it is taken. A Bartlett pear, which normally ripens 
quickly, will ripen and break down in a few days after removal. 
If ripe or overmature when removed, it will decay much more 
quickly, and in either condition its deterioration will be hastened 
if the weather is unusually hot and humid. In the practical man- 
agement of this variety it is fundamentally important that it be 
taken from storage while it is still firm and that it be kept as cool 
as possible after withdrawal. It is probably true that all fruits 
from storage that are handled in hot weather will deteriorate 
quickly, but it appears to be equally true that similar fruits that 
have not been in storage break down with nearly the same rapid- 
ity, if they are equally ripe. The late pears, which ripen more 
slowly, if withdrawn in cool weather will remain firm for weeks 
when held in a cool room after withdrawal. If overripe they 
break down much sooner, and a hot room hastens decay in either 
case. The same principles hold equally true with apples. The 
winter varieties, if firm, may be taken to a cool room and will 
remain in grood condition for weeks and often for months and 
will at the same time retain their most delicate and palatable 
qualities, but in the spring, when the fruit is more mature and 
the weather warmer, they naturally break down very much more 

In commercial practice fruits of all kinds are often left in the 
storage house until they are overripe. The dealer holds the fruit 
for a rise in price, but sometimes removes it, not because the 
price is satisfactory, but because a longer storage would result 
in serious deterioration. If considerable of the fruit is decayed 
when withdrawn, the evidence is conclusive that it has been stored 
too long. Fruit in this condition normally decays in a short time, 
but the root of the trouble lies not in the storage treatment, but 
rather in not having offered it for sale while it was still firm. 
In the purchase of cold storage fruit, if the consumer wHl exer 
cise good judgment in the selection of sound stock that is neither 


fully mature nor overripe, he will have little cause to complain 
of its rapid deterioration. 


A cold storage warehouse is expected to furnish a uniform 
temperature in all parts of the storage compartments throughout 
the season, and to be managed in other respects so that an unusual 
loss in the quality, color, or texture of the fruit may not reason- 
ably be attributed to improper handling or neglect. 

An unusual loss in storage fruit may be caused by improper 
maturity, by delaying the storage after picking, by storing in an 
improper temperature, or by the use of an unsuitable package. 
The keeping quality is influenced by the various conditions in 
which the fruit is grown. 

Pears should be picked before they are mature, either for 
storage or for other purposes. The fruit should attain nearly 
full size, and the stem should cleave easily from the tree when 

The fruit should be stored at the earliest possible time after 
picking. A delay in storage may cause the fruit to ripen or to 
decay in the storage house. The effect of the delay is most 
serious in hot weather and with varieties that ripen quickly. 
(See Figs, i, 2 and 3.) 

The fruit should be stored in a temperature of about 32** 
F., unless the dealer desires to ripen the fruit slowly in storage, 
when a temperature of 36° or 40° F., or even higher, may be ad- 
visable. The fruit keeps longest and retains its color and flavor 
better in the low temperature. It also stands up longer when 
removed. (See Figs. 2, 4 and 5.) 

The fruit should be stored in a package from which the 
heat will be quickly radiated. This is especially necessary in 
hot weather and with quick-ripening varieties like the Bartlett 
pear. For the late pears that are harvested and stored in cool 
weather it is not so important. Bartletts may ripen in the center 
of a barrel before the fruit is cooled down. A box holding not 
more than 50 pounds is a desirable storage package, and it is not 
necessary to have it ventilated. The chief value of a ventilated 
package lies in the rapidity with which the contents are cooled, 
but long exposure to the air of the storage room causes the fruit 
to wilt. (See Fig. 6.) 


Ventilation is essential for large packages, especially if the 
fruit is hot when stored and ripens quickly. 

A wrapper prolongs the life of the fruit. It protects it from 
bruising, lessens the wilting and decay, and keeps it bright in 
color. A double wrapper is more efficient than a single one, and 
a good combination consists of absorptive unprinted news paper 
next to the fruit, with a more impervious paraffin wrapper out- 
side. (See Figs. 7 and 8.) 

The quality of a pear normally deteriorates as it passes ma- 
turity, whether the fruit is in storage or not, or it is never fully 
developed if the fruit is ripened on the tree. The quality of 
the quick-ripening summer varieties deteriorates more rapidly 
than that of the later kinds. Much of the loss in quality in the 
storage of pears may be attributed to their overripeness. The 
quality is also injured by impure air in the storage rooms, and 
the warm summer pears will absorb more of the odors than 
the late winter varieties. The fruit will absorb less if cool when 
it enters the storage room. The air of the storage room should 
be kept sweet by proper ventilation. 

The rapidity with which the fruit breaks down after re- 
moval depends on the nature of the variety, the degree of ma- 
turity when withdrawn, and the temperature into which it is 
taken. Summer varieties break down normally more quickly 
than later kinds. The more mature the fruit when withdrawn the 
quicker deterioration begins, and a high temperature hastens de- 
terioration. If taken from the storage house in a firm condition 
to a cool temperature, the fruit will stand up as long as other 
pears in a similar degree of maturity that have not been in 

It pays to store the best grades of fruit only. Fruit that is 
imperfect or bruised, or that has been handled badly in any re- 
spect, does not keep well. 


Cold storage has not materially influenced the development 
of the American peach business, and it is not likely to do so to 
any extent in the future. In the early days of peach growing 
the industry was localized in sections like the Chesapeake penin- 
sula, New Jersey, and Michigan. The use of the fruit in consid- 



erable quantities was then limited to a few nearby markets and to 
a short time in July, August and September. Now peach growing 
is rapidly extending to all parts of the country where the climatic 
conditions and the facilities for- transportation are favorable. The 
refrigerator-car service has brought the peach belts and the dis- 
tant markets close together, and whenever the crop is general 
the New York or the Chicago trade may be supplied almost 
continuously from May till late October with fruit from Florida, 
Texas, Georgia, the Chesapeake peninsula, New Jersey, the 
Ozark mountain region, Michigan, New England, California, 
West Virginia, western Maryland, and other peach-growing sec- 

The chief value of cold storage to the peach industry will 
probably lie in the temporary storage of the fruit during an 
overstocked market, when, however, there is a reasonable pros- 
pect of a better market within two or three weeks. It might be 
useful also in filling the gaps between the crops of different 
regions, especially when there are local failures which prevent a 
continuous supply. It is not now profitable to store the fruit for 
any length of time, nor under any circumstances unless the 
condition of the fruit and the storage conditions are most favor- 
able. The life processes in the peach and the weather conditions 
in which it is handled make it even more critical as a storage 
product than the delicate Bartlett pear. In normal ripening it 
passes from maturity to decay in a few hours in hot, humid 
weather. The aroma and flavor are most delicate in character 
and are easily injured or lost, and the influence of any misman- 
agement of the fruit in the orchard, in transit, or in the storage 
house is quickly detected by the consumer. 


Under the most favorable conditions known at present, peach 
storage is a hazardous business. Before the fruit is taken from 
the storage house the flesh often turns brown in color, while 
the skin remains bright and normal. If the flesh is natural in 
color and texture it frequently discolors within a day or two 
after removal. There is a rapid deterioration in the quality of 
stored peaches when the fruit is held for any length of time, the 
delicate aroma and flavor giving way to an insipid or even bitter 


taste. Sometimes the flesh dries out, or under other conditions 
it may become "pasty." Dealers in storage peaches frequently 
sell them in a bright, firm condition, and shortly afterwards the 
purchasers complain of the dark and worthless quality of the 
flesh. It has often been noticed that fruit in the various packages 
in the same room does not keep equally well, some of it ripening 
and even softening while the fruit in other packages is still firm. 
In fact, the difficulties are so numerous that few houses attempt 
to store the fruit. 

It has been the aim in the cold storage investigations of the 
Department of Agriculture to determine, as far as possible, the 
cause of the peach-storage troubles and to indicate the conditions 
under which the business may be more successfully developed. 


The investigations were conducted in the cold-storage de- 
partment of the Reading Terminal Market in Philadelphia, Pa., 
with Elberta peaches from the Hale Orchard Company, Fort 
Valley, Ga., and in the warehouse of the Hartford Cold Storage 
Company, Hartford, Conn., with Elberta and several other varie- 
ties grown by J. H. Hale at South Glastonbury, Conn. 

In Georgia the fruit was packed in the Georgia peach car- 
riers, left unwrapped, and divided into two lots, one representing 
fruit that was nearly full grown, well colored, and hard; the 
other, highly colored fruit, closely approaching but not yet mel- 
low. Three duplicate shipments were forwarded at different 
times in the two bottom layers of refrigerator cars, and in 
each shipment part of the fruit was placed in the car within 
three or four hours after it was picked, and an equal quantity 
delayed in a packing shed from ten to fifteen hours during the 
day before it was loaded. Equal quantities of each series were 
stored in temperatures of 32°, 36**, and 40° F. The transfer from 
the refrigerator car to the storage house was made by wagon at 
night, the interval between the car and storage varying from 
two to five hours. 

In Connecticut the fruit represented two degrees of matu- 
rity, similar to the Georgia shipments, except that the most ma- 
ture fruit was mellow when stored. This fruit was grown at 
an elevation of 450 feet on trees six years old. It was medium 


in size, firm, highly colored, and of excellent shipping quality. 
Equal quantities were wrapped in California fruit paper and 
left unwrapped, and packed in the Connecticut half-bushel bas- 
ket, in Georgia carriers, and in flat, 20-pound boxes, holding 
two layers of fruit. The peaches were forwarded by trolley to 
the storage house, which was reached in two hours after the 
fruit left the packing shed. Duplicate lots of all the series were 
stored in temperatures of 32°, 36°, and 40° F. 


The general outcome of the experiments, both with the 
Georgia and the Connecticut fruit, is similar and may be summed 
up as follows: 

The fruit that was highly colored and firm when it entered 
the storage house kept in prime commercial condition for two 
to three weeks in a temperature of 32° F. The quality was 
retained and the fruit stood up two or three days after removal 
from the storage house, the length of its durability depending 
on the condition of the weather when it was removed. After 
three weeks in storage the quality of the fruit deteriorated, 
though the peaches continued firm and bright in appearance for 
a month, and retained the normal color of the flesh two or three 
days after removal. If the fruit was mellow when it entered 
the storage house it deteriorated more quickly, both while in 
storage and after withdrawal. If unripe it shriveled consider- 

In a temperature of 40° F. the ripening processes pro- 
gressed rapidly, and the flesh began to turn brown in color after 
a week or ten days in storage. The fruit also deteriorated much 
more quickly after removal, as it was already nearer the end 
of its life history. It began to lose in quality at the end of a 

In a temperature of 36° F. the fruit ripened more rapidly 
than in 32°, and more slowly than in 40'' F. It reached its 
profitable commercial limit in ten days to two weeks, when the 
quality began to deteriorate, and after this period the flesh be- 
gan to discolor. 

Fig. 9 shows average condition of Georgia Elberta peaches 
two weeks in storage after forty-eight hours withdrawal to a 




warm room. The upper specimen represents the average condi- 
tion of fruit stored in a temperature of 36'' F. The lower speci- 
men represents the average condition of the fruit stored in 
32° F. The lower temperature gave better results in every 

The fruit kept well in all of the packages in a temperature 
of 32° F. for about two weeks, after which that in the open bas- 
kets and in the Georgia carriers began to show wilting. In the 
20-pound boxes, in which the circulation of air is restricted, 
the fruit remained firm throughout the storage season. 

It is necessary that the fruit be packed firmly to prevent 
bruising in transit, but if the peaches pressed against each 
other unduly it was found that the compressed parts of the flesh 
discolored after a week in storage. A wrapper proved a great 
protection against this trouble, especially in the baskets of the 
Georgia peach carrier, and in all of the packages the wrapped 
fruit retained its firmness and brightness for a longer time than 
that left without wrappers. 

The fruit should be removed from storage while it is still 
firm and bright. The peach normally deteriorates quickly after 
it reaches maturity, and the rapidity of deterioration is influenced 
by the nature of the variety, by the degree of ripeness when 
removed, and by the' temperature into which it is taken. A 
quick ripening sort, like Qiampion, is more active biologically 
and chemically than the Elberta variety, and the warmer the tem- 
perature in which either is placed the sooner decomposition is 
accomplished. It is advisable, therefore, to remove the fruit 
while firm and keep it in the coolest possible temperature. 

The peaches in the top of a refrigerator car that has been 
several days in transit in hot weather are sometimes overripe 
and need to be sold as soon as the market is reached, while at 
the same time the fruit in the bottom layers may still be firm. 
The rapidity with which the fruit cools dow^n in the car depends 
on the care with which the car is iced, and on the temperature at 
which the fruit enters the car. Fruit that is loaded in the middle 
of a hot day and that has been picked in a heated condition may 
be 20 or more degrees warmer than fruit picked and loaded in 
the cool of the morning. Such warm fruit ripens much more 
rapidly, consumes more ice in cooling down, and takes longer 


to reach a low temperature. When the temperature in the top 
of the car is higher than that of the lower part the ripening of 
the upper layers of fruit will be hastened. If the fruit is des- 
tined for cold storage, these upper layers, if more mature, should 
be piled separately, and sold as soon as their condition warrants 
it. Under these conditions, if the fruit from this position is 
mixed in with the rest of the load it may begin to deteriorate be- 
fore the remainder of the fruit shows mellowing. 

The general principles outlined in former pages for the 
handling of the Bartlett pear apply to the storage of the peach, 
except that the latter fruit is more delicate and the ripening 
processes are even more rapid. Every condition, therefore, sur- 
rounding the peach in the orchard, in transit, in the storage house, 
and at withdrawal must be m<^t favorable. The fruit must be 
well-grown and well-colored but firm when picked. The packing 
must be done with care to prevent bruising. If the fruit is to be 
transported in refrigerator cars, it should be loaded soon after 
picking, and preferably before it loses the cool night temperature. 
The peaches should be transferred from the cars to the storage 
house, or from the orchard to the storage house if the latter is 
near the orchard, in the^quickest possible time. The air of the 
storage room should be kept sweet and pure. The fruit should 
always be removed to the coolest possible temperature, usually 
at the end of two weeks, while it is still firm, and it should be 
placed in the consumer's hands at once. 

If the fruit is overripe when picked, or becomes mellow 
from unfavorable handling before it enters the storage house, 
it is already in a critical condition and may be expected to de- 
teriorate quickly. 

If the conditions outlined are observed in the handling of the 
peach, it is possible to store it temporarily with favorable re- 




The experiments conducted by the United States Depart- 
ment of Agriculture (described in previous chapters) to deter- 
mine the best methods of handling and storing fruits have re- 
sulted in securing information of much value. Information be- 
fore well known to the author and others connected with the 
industry has been verified by the experiments and put in the 
form of plain statements of facts. It has been fully demon- 
strated that better results are secured by the placing of fruit in 
storage promptly when picked, and that fruit, especially apples, 
should remain on the trees until well colored and fairly ripened 
before picking for storage. These facts argue strongly in favor 
of the fruit grower operating his own cold storage. Professor 
G. Harold Powell, who had the experiments in charge, says: 
"The local warehouse is ideal for quick storage and for the 
grower who is competent to handle his own crop. Capital has 
developed the warehouse business in the large cities, as it is 
more convenient to distribute the fruit from them and more 
economical to maintain a plant where a general storage business 
can be operated. But as the importance of quick storage at 
harz'est time is more generally appreciated, it will probably lead 
to a greater development and concentration of local storage houses 
and to a greater use and improvement of the refrigerator car serv- 
ice. * * * I believe that one of the developments that will take 
place in the future is the building of warehouses in the apple 
producing regions, and the distribution of the product from these 
warehouses in cooler weather." The part in italics is used by the 
author to emphasize the point under consideration, viz.: That 
best results and greatest profits to the grower can only be secured 

♦Extracted from a series of articles written for Green's Fruit Grower by the author 


by placing the fruit in cold storage as soon as removed from the 
trees. This does not necessarily mean that the grower must have 
a cold storage house on his premises, although in many cases this 
is the best and most practical plan; but the cold storage house 
should be easily accessible in order to secure the best results. 
Many fruit growers are at present so situated that their fruit is 
packed in barrels and shipped by refrigerator car to the nearest 
storage point, requiring only two or three days in transit. Even 
this short time causes deterioration of some of the softer varieties 
of fruit, as the warm fruit going to the car cooled with ice only 
will not in all probability become cooled below 45° or 50° F. 
With a local cold storage the fruit requiring quick work may be 
cooled down rapidly to a temperature of 30° F., thus improving 
its keeping qualities, and shipped out later in the season when 
outside temperatures are lower. Many times refrigerator cars 
are not available and the damage is then much greater. 

As an instance of one of the benefits to be derived from 
home cold storage may be cited the barrel situation in the east 
during the season of 1903. It was impossible to obtain barrels 
in sufficient quantity to take care of the crop at harvest time, and 
it is reasonable to say that many thousands of dollars were lost 
to the grower from this reason on account of deterioration of 
quality of fruit while lying in the orchards waiting for barrels. 
In many cases total losses occurred. Apples may be successfully 
stored without barrels; and boxes and crates are regularly used 
for this purpose. They may also be stored in bulk, but this is 
not as good. A grower provided with suitable cold storage 
facilities does not have to wait for barrels. 

Apples to stand shipment long distances before placing in 
storage must be picked while still somewhat immature. The 
bothersome apple scald is increased by too early picking, as 
it has been shown by the experiments and by practice that ma- 
ture, well colored fruit does not scald to any extent. On this 
score Professor Powell states: "The experiments indicate that 
so far as maturity is concerned, the ideal keepmg apple is one 
that is fully grown, highly colored, but still hard and firm when 
picked. Apples that are to be stored in a local cold storage house 
to be distributed to the markets in cooler weather may be picked 
much later than fruits requiring ten days or more in transit. 


* * * Therefore, to sum up in a general way, the results of 
the experiments which have been made seem to indicate that the 
ideal fruit for storage purposes is that which is taken from the 
tree to the warehouse in the quickest possible time, in order to 
prevent the fruit from consuming a large proportion of its own 
life history during the delay that may take place." 


These are some of the benefits of home or local cold storage. 
Many instances could be cited where large profits have been 
made by placing fruit in cold storage for a time and selling when 
the market was comparatively bare, but these seasons are excep- 
tions, and in going into a cold storage proposition, the grower 
should not expect more than a reasonable profit, amounting to 
interest and a fair remuneration for the risk assumed. One 
season with another, a good profit is certain if the business is as 
well handled as it should be, and none but a careful person of 
methodical habits will succeed in the operation of a cold storage 
plant. In the future the grower with modern cold storage fa- 
cilities will have the advantage over his less progressive neighbor 
from the fact that his losses will be less and he will be able to 
place in the hands of the consumer a better preserved and more 
attractive grade of fruit. 

The question may arise as to the probable result of the 
erection of a much larger number of cold storage houses than 
are now in use throughout the section of the country where com- 
mercial orcharding is largely practiced, and also the probable 
result of the great increase of acreage of fruit bearing trees. The 
application of cold storage is still in its infancy. It cannot be 
said that its use so far has been in any way detrimental to the 
development of the industry, on the contrary, it has been a great 
benefit, as fruit growers well know. If the development of cold 
storage has been beneficial in the past, why should not further 
development be beneficial? It may be true that the profits will 
not be as great in the future with more storage houses in use, 
but the profits will be more certain and regular. The old cry of 
overproduction has been raised in connection with fruit growing 
and storing, but with the country only half populated, growing 
fast, and with developing tastes and rapid improvements in trans- 


portation, overproduction is impossible. If there has at times 
been a temporary overproduction in the past, it has not been due 
to a surpUis, but to lack of facilities in distributing and trans- 
portation. Commercial orcharding is rapidly expanding and cold 
storage will be necessary as an auxiliary. There can be no dis- 
astrous glut of the market when cold storage will absorb the 
surplus at harvest time and distribute it as needed by refrigerated 
transportation to the markets of the world. Nearly every one 
can remember when the cold storage of apples was almost un- 
known — they were stored in basements, cellars or "fruit houses" 
without refrigeration. Probably a few are still doing this, but 
it is safe to say that not more than 30 or 40 per cent of the fruit is 
so stored for temporary purposes, and storers of this 30 or 40 per 
cent would save money in improving the quality of the fruit by 
employing artificial refrigeration. Owing to the considerable in- 
vestment necessary it is improbable that the construction of cold 
storage plants will ever be on a scale large enough to cause an 
oversupply of cold storage space, but the time will shortly arrive 
when practically all perishable goods will be handled in and sold 
from cold storage. Those who first provide themselves with 
cold storage will be the ones to be benefited largely thereby. 


The absolute necessity of cold storage at or near the orchard 
in order to secure the most perfect results seems unquestionable. 
What then should a modern cold storage plant consist of? The 
answer depends largely upon climatic conditions and extent and 
character of the crop to be handled. We will here consider only 
the needs of the comparatively small grower who will store say 
from 200 to 2,000 barrels. The use of natural ice for cold storing 
of fruit dates back thirty years or more. As has been previously 
pointed out, and as generally understood among the trade, the 
natural ice systems with which we are all more or less familiar 
have not been generally successful for tne purpose. The chief 
objections to these methods were found to be lack of control as 
to temperature and too much moisture in the air of the rooms. 
The lowest dependable temperature during warm weather was 
about 38° to 40° F., oftentimes higher. The moisture in the air 
was excessive at times, especially during cold weather when the 



temperature was lowest in the storage room. At the present time 
a temperature of 30 "^ F. is considered best for apple storage, and 
any apparatus which cannot produce this temperature cannot be 
considered for practical purposes as a modern system. Humidity 
also should be under control. It is for this reason that the ice 
systems have gone into disuse, and the ammonia or mechanical 
systems are understood to be the best. The advantages of sim- 
plicity and low operating cost when using ice for cooling, com- 
bined with the positive control of temperature and moisture ob- 
tainable with the ammonia or mechanical system, are all em- 


bodied in the gravity brine system, described in a previous chap- 
ter. This system has none of the disadvantages of complicated 
machinery, requiring skilled labor, as is necessary with the me- 
chanical or chemical systems. 

The buildings here illustrated are planned to meet the needs 
of those who have a crop large enough to make storing profitable. 
Tt is not recommended that a cold storage plant of less capacity 
than 200 to 300 barrels be built, except under special local con- 
ditions which might warrant a smaller capacity. The cost of con- 
structing a very small house is greater in proportion as will be 
seen by the subjoined estimates. The cost of operating is also 



greater in proportion and the time and care necessary to make 
a success of a very small plant will operate a much larger one 
equally well. The relative cost of a plant of 600 barrels capacity 
and one of 1,500 barrels capacity are here figured with some de- 
gree of accuracy for average conditions. The operating cost 
would be in about the same proportion. The cost of building and 
operating a house of say 300 barrels would be more than half 
as much as the house here described for 600 barrels. It will be 
apparent that an extremely small house is not profitable under 
average conditions. 


Plan No. I, which is illustrated by perspective, plan and 
sectional views (see Figs, i, 2, 3 and 4), is suitable for a capacity 
of from 200 to 1,000 barrels of apples or other fruit, without 
change in arrangement of rooms and general plan of building. 
The cold storage space consists of a large storage room 12 feet 
in height, which may easily be maintained at a temperature of 30° 
F. during the warmest midsummer weather, and a smaller cooling 
room, shown in Fig. 2, 8 feet in height, which is used for bringing 
down the temperature of the fruit partly before placing in the large 



storage room. Access to the storage room is only had through the 
cooling room, preventing at all times the inflow of warm air. This 
cooling room is most useful during comparatively warm weather, 
for instance, while storing the summer or winter varieties of 
fruit, or for cooling and storing Bartlett pears or similar fruit 
which require quick cooling. By placing the fruit over night 
in the cooling room a large part of the heat may be removed and 


then, when removed to the storage room no marked change of 
temperature will take place. The cooling room has pipe coils 
of sufficient capacity to carry a uniform temperature of 30° F. 
during the cold weather of fall and winter and this room may be 
used for permanent storage of the hardy winter varieties which 
are not placed in storage as a rule until cold weather in the fall. 
The cooling room is entered from a packing or receiving room, 
as it is generally called. The packing room may be made larger 
if desired, or it may be omitted if cold storage is to be built adja- 



cent to a fruit packing shed already in use. The packing 
room is provided with a chimney, so that a fire may 
be built in extreme cold weather if necessary to prevent low 
temperature in the storage room and cooling room, or when it is 
desired to work in packing room in winter. From the packing 
room, stairs lead up to lofts above storage, packing and cooling 
rooms. These lofts are useful for the storage of empty packages, 
etc. The ice room adjoins both the packing and storage rooms, 


and is thus protected from the sun on two sides. There are no 
openings from the ice room to any part of the building except 
to tank house for the purpose of raising ice to tank. 

Plan No. 2 (illustrated in Figs. 5, 6, 7 and 8) is in most 
respects like plan No. i, but is adapted to larger houses. Plan 
No. 2 may be readily built ranging in capacity from 1,000 to 
2,000 barrels. The estimate is based on a capacity of 1,500 bar- 
rels. The ice room is placed at one end of the house in this case 



and the storage room between the ice room on one side and pack- 
ing and cooHng rooms on the other. The storage, cooling and 
packing rooms bear the same relation to each other and are of 
the same height and similarly equipped as in plan No. i. 

It should be understood that both these plans include about 
as much space in the packing room and lofts as is contained in 
the storage rooms equipped with the cooling apparatus. In 
case it is desired to dispense with this storage space for empty 
packages, etc., as would be the case when the cold storage was 


built against a barn or fruit house already existing, a considerable 
saving could be had by some slight changes in plans. Old build- 
ings may be remodeled in most cases to good advantage and a 
handsome saving thereby effected. The estimates here given 
are for good, though plain construction, and cold storage houses 
built in this way will do good service for many years. 

The estimated cost of constructing and insulating a cold 
storage house of 600 barrels capacity on plan No. i is $1,365. 
The cost of refrigerating equipment, consisting of piping, gal- 
vanized iron work, etc., $650, making a total of $2,015. Plan 
No. 2 is estimated at $2,545 for building and $1,075 ^^^ equip- 



ment, total $3,620. These figures are based on average costs 
and conditions, and will of course vary somewhat in different 
sections. Country locations are usually much cheaper to build 
in than cities, but this is not always true. 

The ice room in this style cold storage house is merely a 
storage place for ice, and there are no openings from the ice intor 



the storage part of the building. The ice room is to be filled in 
winter, and will accommodate sufficient ice not only for the 
operation of the cold storage plant for an entire season, but for 
any ordinary farm or family uses as well. Xo packing material 
of any sort is used on or around the ice. The floor, sides and 




ceiling of ice room are well insulated with mill shavings or some 
similar material. This saves considerable unpleasant labor in 
taking out ice, and the ice will keep as well or better than it will 
in the old style way of covering with sawdust or other material. 
The ice is also clean and ready for use when taken out. Ice is 
filled into the ice room through an ice door extending from floor 
to ceiling, consisting of inner and outer sections which are filled 
between with shavings or other material after filling the room 
with ice. Ice may be removed from the ice room for' uses out- 
side of the building through the filling door. Ice for use in the 


primary tank of the gravity brine system is first broken or pul- 
verized in the ice room and then raised by a rope through a trap 
door to the tank house. 

The operation of the gravity brine system which cools the 
rooms is based on well known natural laws that heat expands and 
cold contracts. 

For cold storage houses of a capacity greater than about 
2,000 barrels of fruit, the complete "Cooper Systems" are in- 
stalled. (For description of the Cooper systems sec chapter on 
^'Refrigeration from Ice.") In addition to the gravity brine 



system and chloride of calcium process, they consist of the forced 
air circulating and ventilating systems, viz., an improved method 
of circulating the air of the storage rooms over the secondary 
coils in the storage rooms, and a system for ventilating cold 
storage rooms by the forcing in of air which has been thoroughly 
purified, dried, and brought to about the temperature of the 
storage room. These air circulating and ventilating systems are 


necessary in larger houses where the arrangement is more com- 
plicated and the rooms are larger and the natural circulation 
of the cooled air is not uniform in all parts of the rooms ; thus 
making advisable the use of a forced air circulation induced by 
a power driven fan. On account of requiring continuous power, 
the air circulating system has not been applied to the small houses 
here described. 




It is within recent years that the digging of trees from 
nursery row in the fall and storing during the winter for spring 
shipment has come to be an established feature of the nursery 
business. This subject was brought to the author's attention by 
a discussion between nurserymen of the advisability of the 
method. In this discussion the term "cold storage" was 
used in reference to the cellars or sheds in use for the purpose. 
Having a great interest in cold storage matters, the author de- 
termined to get the best information obtainable from those actu- 
ally using the storage method. Letters of inquiry were therefore 
sent out to representative nurserymen. That nurserymen are 
in the main progressive and liberal minded is evident from the 
interest shown and the careful replies received. The author 
hopes that nurserymen will excuse the conceit which allows an 
outsider to write regarding a business with which he is not inti- 
mately familiar. This chapter, however, gives no mere theory 
or opinion by the author, but information carefully gleaned from 
those actually engaged in the business and put in shape by one 
who has had a long experience with the cold storage of perishable 

From the information obtained, it is beyond doubt a fact 
that a majority of nurserymen, especially the larger and more 
progressive, are using frost-proof winter storage facilities of one 
kind or another. A few are using artificial cooling, but as a gen- 
eral proposition, this is not as yet fully appreciated. In time, no 
doubt, this feature will also come to be permanent, not only for 
maintaining regular temperatures during winter, but should 
there be an overstock of certain varieties in the spring, it would 

♦Originally published in The National Xurseryman by the Author. 


result in a great saving to store the surplus over until the next 
shipping season. Artificial cooling is another step in advance of 
frost-proof storage in the same sense that fall digging and frost- 
proof storage is a step in advance of the old method of digging 
at shipping time in the spring. It is natural that every planter 
should want his trees immediately as soon as the frost is out of 
the ground. The result is that they all want their stock at the 
same time. As a consequence, nurserymen who do any consid- 
erable amount of business and have no storage facilities have 
more than they can attend to in the spring. Even with this almost 
impossible problem to solve, there are many who are not con- 
verted to the storage method, so a few words regarding its ad- 
vantages and alleged disadvantages will be timely. The ad- 
vantages may be stated as follows : 

I. — Protection from Loss: — A few years ago thousands of dol- 
lars' worth of trees and vines were killed during a severe 
spell of extreme low temperature during the winter at a 
time when the ground was nearly bare of snow. It is also 
believed that nursery stock is in better condition to thrive 
when dug in the fall and stored in an even temperature 
approximating the freezing point than if allowed to stand 
in the nursery subject to wide fluctuations of temperature 
which will cause injury to a greater or less extent, depend- 
ing upon severity of the winter and snow protection afforded. 

2. — Prompt Shipment: — If no storage is provided digging must 
be done in the spring after frost is out of the ground. Frost 
is not generally out of the ground until April i, sometimes 
later. This means that a large part of the trees are not 
finally planted until May i to June i, and perhaps not 
until the leaves have started. Trees set under those condi- 
tions do not thrive as well and many die. 

3. — Saving in Labor: — The shipping season is so short that if 
trees were all dug and shipped after frost is out of the 
ground the necessity of having a large and well trained force 
to get the shipments out promptly would be very expensive. 
With storage facilities, stock can be graded at convenience, 
counted and put in bundles ready for packing by cheap help 
during the winter. Trees may be dug in the fall at a much 


lower cost than in the spring, owing to more abundant avail- 
able labor and dryer working conditions. Less hands are re- 
quired as the labor is more evenly distributed. 
4. — Theoretically Correct: — Trees dug late in the fall are dor- 
mant from natural causes and will stand handling, shipping 
and planting much better than trees dug after frost is out 
of the ground in the spring. After frost is out, sap starts 
and the tree is more liable to be damaged by rough usage 
and replanting. A dormant tree held at about the freezing 
point will retain its vitality almost indefinitely. 

The disadvantages or bad effects of winter storage as claimed 
by those who oppose the method, are that trees dry out and mould 
when stored and that when finally set the percentage of trees 
which die is greater. It is also claimed that among the stock 
which survives, the growth is retarded and the trees handicapped 
by at least a year's growth as compared with freshly dug trees. 
Plenty of evidence is obtainable from disinterested parties that 
these effects result in some cases. These bad effects are, how- 
ever, not from defects in the method, but from careless or unskill- 
ful handling, or lack of suftable storage facilities. Farther on 
we will take up the construction of suitable buildings. It is 
notable that the advocates of freshly dug trees are almost wholl)' 
of the '*old line" element who stick to old customs, because some 
few failures have resulted from the winter storage method. This 
method, which has barely passed the experimental stage, can not 
but record some failures on account of improper application. 
Nurserymen who practice the selling of freshly dug trees are 
handicapped in the handling of their business, and the increasing 
of same to any considerable proportions is practically impossible. 
From the preponderance of evidence in favor of winter storing, 
it seems that this will be universal in due time. We have then 
to consider the most approved methods now in use and sugges- 
tions for possible improvements. 


Some of the nurserymen who do not advocate winter stor- 
age, admit the need of something better than spring digging by 
^'heeling in" or "trenching" their trees for the winter in a pro- 


tected place which will drain naturally. They admit that this 
allows of possible damage to the tops of the trees in severe 
weather, but it saves time and wet digging in the spring. As 
an improvement over this it is only another step towards the solu- 
tion of our problem to put a shed over these heeled-in trees to pro- 
tect the tops from low temperature during severe weather. This 
is a common method and is practiced by some very large nursery- 
men. A frost-proof cellar or shed is provided in which the trees 
are heeled-in in the fall, so as to have them ready for spring ship- 
ment. The storage shed is kept at the freezing point or some- 
what above, so that sorting, grading and packing may go on inde- 
pendent of weather conditions outside, enabling shipments to be 
made as early as desirable in the spring. Much storage space is 
needed with this method and under such conditions the trees may 
dry out or shrivel, but the heeling-in in storage method has the 
advantage of being more independent of temperature changes 
than where the stock is piled up with roots exposed. A change of 
temperature is largely what causes the drying out of trees, owing 
to the change of humidity with the temperature changes. 

Most of the winter storage structures in service are built 
partly below the surface, but many of the largest are wholly above 
the ground. Nearly all are insulated by building air spaces into 
the walls or by a filling of shavings, sawdust or similar non-con- 
ducting materials. It is the idea in building partly below ground 
to secure the protection afforded by the earth. It is a well known 
fact that at a depth of a few feet below the surface of the earth a 
nearly stationary temperature of about 55° F. may be obtained 
winter and summer. This will prevent freezing in winter if the cel- 
lar is rightly built, but it will likewise cause a marked rise in tem- 
perature whenever a winter thaw occurs and it becomes necessary 
to close the building tightly. The heat of the earth will then 
work up into the storage room and a temperature of 40° F. to 
50° F. may result. Another disadvantage of the cellar is that 
when the first trees are stored during the fall, the surface of the 
earth is quite warm, and it is very difficult to keep the tempera- 
ture of the cellar low enough. Ventilators, windows and doors 
are opened on a cold day or at night, and in this way the tem- 
perature is, after considerable delay, finally reduced to the desired 
point. A warm spell alternating with cold weather in the fall 


after storing commences will cause a great deal of damage by 
causing the temperature of the cellar to vary greatly. A varia- 
tion of temperature and consequent variation of humidity will 
cause a drying out or shriveling of the trees, and may cause a 
growth of mold or mildew. A building wholly above ground has 
many of the disadvantages above mentioned, and also the disad- 
vantage of lack of protection during extremely cold weather. 
There are, however, advantages in above-ground construction, in 
that, if the building is built of frame, it will not rot out as 
quickly, and it may be cooled more readily in the fall, and it is 
not affected so much by heat from the earth. It is stated by many 
nurserymen that temperatures are very difficult to maintain in 
any of the ordinary sheds or cellars in use, especially during the 
storage season in the fall and during the shipping season in the 
spring. Winter storage for nursery stock should be so arranged 
that wlien natural temperature is suitable, air may be taken from 
the outside and forced into the room for refrigerating, and when 
natural temperatures are not suitable, as during a warm spell 
in fall or spring, or during a winter thaw, artificial refrigeration 
may be applied. Moisture brought in with stock, — especially if 
the fall has been a wet and warm one, — might cause mold. A 
proper cooling and temperature regulating system would pre- 
vent this. 

From the data at hand, it seems clear that practically all 
of the damage to nursery stock experienced in winter storing in 
cellars or sheds as ordinarily practiced, comes from changes of 
temperature, and '\ generally too high temperature, which can 
not by present methods be avoided. It has been noted that trees 
dug late in the fall and placed in storage after the temperature of 
storage room has been reduced to about the freezing point have 
carried through in better condition than those dug at an earlier 
date and placed in storage while the temperature of the room 
was still comparatively high. This may be partly because the 
v/ood is more dormant, but is probably largely because it is easier 
after about November 15 to keep down the temperature of 
the storage room. A high temperature and frequent changes of 
temperature will cause stock to dry out and shrivel. This is 
especially true of vegetation of quick growth, such as peach trees. 
To prevent this drying out, a spraying with water is often resorted 


to, but this again leads to mold or mildew if the temperature is 
high and not very carefully handled. One nurseryman states: 
*'When stock is put in late in October and November, it needs no 
wetting at all, but stays damp all winter and spring;" another 
says : **In our own case, we find on account of the ups and downs 
of temperature, we must sprinkle with water more or less, but 
we believe that with a fixed temperature that did not vary to any 
great extent, the water could be omitted." No better argument 
could be made for low and uniform temperatures. There is no 
question at all that trees may be dug any time after October 
I, or after the tree is dormant from natural causes, placed in a 
temperature of from 28° to 30° F., held steadily until spring, and 
come out in better condition for planting than stock allowed to 
remain in the nursery all winter and dug at the shipping time. 
Humidity must be attended to, but this is very easy to regulate 
at the low temperatures mentioned. As to temperatures at which 
trees should be held there seems to be a wide difference of 
opinion ; no doubt this opinion is largely influenced by the tem- 
peratures it is possible for each individual nurseryman to main- 
tain in his storage cellar. Nearly all admit the difficulty of keep- 
mg uniform temperatures, and opinions as to correct temperatures 
vary from 30° to 50° F. No doubt 30° F. will produce better 
results than any of the higher temperatures. It has been demon- 
strated in the history of preserving perishable products by refrig- 
eration that the lower the temperature at which any particular 
product may be carried without damage from such low tempera- 
ture, the better and longer it may be kept in cold storage. Cer- 
tainly a temperature of 30° F. can not injure nursery stock if it 
is able to withstand severe winter weather with any degree of 
safety. It seems reasonable, therefore, that this is a suitable tem- 
perature to maintain. 


At a temperature of 30° F. the air contains very little mois- 
ture, and in fact it can not hold much, so the possibility of drying 
out nursery stock is much less when stored in a temperature of 
30° F. than at from 40° to 50° F., w^hich many recommend. The 
cai)acity of air for moisture is a direct property of its tempera- 
ture — the higher the temperature, the more moisture air will take 




up and hold. At 30° F. air will hold less moisture than at any 
higher temperature. Air which is saturated wath all the moisture 
it will hold at 30° F. contains 1.96 grains per cubic foot. At a 
temperature of 40° F. ; 2.85 grains per cubic foot. This shows 
the rapid increase in capacity for moisture as the temperature of 
the air is increased. Suppose we are holding our storage room 
for nursery stock at 30 ** F. and a warm spell of weather comes, 
one which obliges us to close tightly all openings leading to the 
outside air. After a few days the temperature goes up to 40° F. 
What is the result ? The air, say, was at the 84 per cent relative 
humidity at 30° F. When the temperature has increased to 
40° F., the relative humidity will be 56 per cent. What does 
this mean? Simply that the air has become comparatively very 
dry and that moisture-containing products like trees will dry 
out very quickly. This case is stated to show the operation of 
this simple natural law in connection with the winter storage of 
nursery stock. Possibly these exact conditions might not occur 
in practice, but they would be approximated. The great import- 
ance of maintaining uniform temperature and humidity is plainly 
illustrated, and the cause of the drying out of trees by fluctuating 
temperatures is readily seen. 

To overcome the difficulties of winter storing as above out- 
lined it is proposed to apply artificial refrigeration when neces- 
sary to maintain sufficiently low temperatures. By the term arti- 
ficial refrigeration it should not be understood that a complicated 
ice machine is necessary. The term is used to express cooling 
effects other than those produced by outside atmospheric condi- 
tions. Such a refrigerating equipment is embodied in the gravity 
brine system described in chapter on " Refrigeration from Ice." 


The accompanying illustrations show a combination winter 
and summer storage building constructed wholly above ground. 
The storage space is divided by a partition into two rooms, one 
small room 30x50 feet, and one larger room 50x80 feet. These 
rooms are both cooled from one battery of pipe coils, but the air 
ducts are provided with gates so that the entire refrigerating 
effort may be applied to the smaller room. The refrigerating 
equipment is of sufficient capacity to maintain a temperature of 



30° F. in the small room during midsummer, and to maintain the 
same temperature in both rooms during comparatively cold 
weather, say from November i to May i. Both rooms may 
be used for winter storage, and during the summer the large 
room may be shut off and only the small room used. If it is not 
desired to store nursery stock during the summer, other goods 
may be taken for storage if they are to be had, or the plant may 
be shut down during the summer. No expense whatever is neces- 
sary when the plant is not in operation. The main part of the 
storage building, 50x110 feet, is essentially like many storage 
cellars or houses now in use, consisting of as plain and as cheap 


a building as can be built, and roughly insulated. At one end of 
the storage building is the ice room, which also contains the com- 
plete refrigerating and mechanical equipment. The ice room is 
50x25 feet on the ground, 30 feet high inside and will hold about 
750 tons of ice, which is more than sufficient to maintain the tem- 
perature as al)ove stated during the year. The room containing 
the secondary coils of the gravity brine system is located on the 
ground. Above this room is located the tanks containing the 
primary coils and the ventilating room containing the heater for 
use during extremely cold weather and at such times as it is 
necessary to warm or dry the storage rooms. The gasoline engine 
or other power used for driving the fan for circulating the air 



through the storage room and for ventilating, is also located in 
the room above the tank and ventilating room, where access is 
had to top of tank for filling with ice. On this floor is also 
provided storage bins for salt. In houses the size of the one 
here illustrated, or larger, an ice crushing machine and ice ele- 
vator as shown is desirable, especially as the power is at hand 
for operating the same. In smaller plants this may be dispensed 

The operation of the plant is as follows: Ice is fed to the 
ice crusher, which reduces it to about the size of hens' eggs; 

FIG. 5 


from the crusher the ice drops into a bucket elevator, which lifts 
it up above the tank containing the primary coils and drops it 
into the tank through a flexible spout. It will be noted that very 
little labor is necessary with this arrangement. As the ice falls 
into the tank a small amount of salt is sprinkled in. This pro- 
duces a low temperature in the tank, which cools the chloride of 
calcium brine in the primary coils and causes a circulation as 
already described. The actual cooling of the storage rooms is 


accomplished by drawing the air in through small ducts on the 
sides of the rooms by means of the fan and causing it to pass over 
the secondary coils of the gravity brine system in coil room, 
where it is cooled; then forcing it from fan into large duct in 
center, where it is evenly distributed to the rooms. When neces- 
sary to heat the storage rooms, the return air to coil room is 
caused to circulate over the large, jacketed heater in ventilating 
room, or fresh air for ventilation may be drawn over heater for 
ventilating and heating at the same time. When weather condi- 
tions are right, a large volume of air from the outside may be 
forced into the storage rooms for the purpose of cooling the 
rooms. Many times greater cooling results may be secured in 
this way than by the opening of doors and windows, and the cold 
air is evenly distributed to the rooms so that no freezing or harm 
can result, as is possible to goods stored near open windows or 
doors on frosty nights. 

The estimated cost of complete apparatus, aside from* the 
buildings, for a house the size shown, completely erected in place, 
is from $2,500.00 to $2,800.00. 

The plant described will maintain uniformly low tempera- 
tures at about the freezing point in the entire building during the 
cold weather when most of the nurserymen's products are stored, 
and in one-fourth of the house during the summer. The initial 
cost of the apparatus is not excessive, the cost of operation almost 
nominal and the results to be obtained positive. Only a moderate 
amount of refrigeration is required in storing nursery products, 
but when reqiiired, it is very important, and the cost is so small 
that it will soon pay for itself in saving of loss and perfection of 
results possible to obtain. In many cases the nurseryman is a 
fruit grower as well, and cold storage would be a good auxiliary 
to add for the purpose of taking care of the softer fruits tem- 
porarily and the hardy fruits for a longer term of storage. 

This description of a suitable plant for nurserymen is de- 
signed for northern locations where the nursery business has 
had greatest development. In the south or extreme west the 
mechanical systems of refrigeration would be best adapted; or 
in a large plant in the north. The other features of the plant 
would remain the same so far as construction, air circulation, 
etc., is concerned. 




In the artificial freezing of fish and their subsequent reten- 
tion in cold storage is found one of the most recent methods of 
food presentations, originating about thirty-five years ago, and 
while it has acquired considerable importance in certain localities, 
its practical value is scarcely appreciated by the general public. 
It is applied in the various marketing centers of the United 
States, and to some extent in the countries of Europe and South 
America. Its greatest development and most extensive applica- 
tion exists along the great lakes, in freezing whitefish, trout, 
herring, pike, etc., about 7,000,000 pounds of which are frozen 
each year. On the Atlantic coast of the United States it is used in 
preserving bluefish, squeteague, mackerel, smelt, sturgeon, her- 
ring, etc., the trade in these "tailing on" or immediately following 
the season for fresh or green fish. On the Pacific coast large 
quantities of salmon and sturgeon are frozen and held in cold 
storage until shipped, the trade extending to all parts of America 
and northern Europe. At various points throughout the interior 
of the country there are cold storage houses where fishery prod- 
ucts are held awaiting demand from the consumers. In Europe 
there is comparatively little freezing of fish, although the process 
is applied very extensively to preserving beef, mutton, etc., and 
the markets of Hamburg and other continental cities receive an- 
nually several m.illion pounds of frozen salmon from our Pacific 
coast. In England large fish freezers were erected several years 
ago at Grimsby and Hull, and trawlers are in some cases supplied 
with refrigerating plants where the fish are plunged alive into 
cold brine which freezes them solid. 

♦By Charles H. Stevenson in Ice and Rt/rigeration, February, 1900. 


During warm weather the temperature of the fish storage 
room can never be kept below 32° F. by the use of ice alone. 
While a temperature of 32° F. retards decomposition, the fish 
acquire a musty taste and loss of flavor, and eventually spoil. 
To entirely prevent decomposition the fish must be frozen imme- 
diately after capture, and then kept at a temperature of several 
degrees below freezing. The belief held by some persons that 
freezing destroys the flavor of fish is not well founded, the result 
depending more on its condition when the cold is applied and the 
manner of such application than upon the eflfect of the low tem- 
perature. Fish decreases less in value from freezing than meat 
does, but it is especially subject to two difficulties from which 
frozen meat is free; first, the eye dries up and loses its shining 
appearance after considerable exposure to cold, and second, the 
skin, being less elastic than the texture of the fish, becomes hard 
and somewhat loose on the flesh. Frozen fish is not less whole- 
some than fish not so preserved. The chemical constituents are 
identical, except that the latter may contain more water, but 
the water derived from in jested fish has no greater food value 
than water taken as such. The principal objection to this form 
of preservation is the tendency to freeze fish in which decomposi- 
tion has already set in, and the prosperity of the industry requires 
that any attempt to freeze fish already slightly tainted should be 
discountenanced. When properly frozen and held for a reason- 
able period, the natural flavor of fish is not seriously affected 
and the market value approximates that of fish freshly caught. 
The process is of very great value to the fishermen supplying 
the fresh fish trade, since it prevents a glut on the market, and 
it is also of benefit to the consumer in enabling him to obtain 
almost any variety of fish in an approximately fresh condition 
throughout the year. 


The first practical device for the freezing and cold storage 
of fish was invented by Enoch Piper, of Camden, Me., to whom 
a patent was issued in 1861. His process, based on the well 
known fact that a composition of ice and salt produces a much 
lower temperature than ice alone, consisted in placing the fish 
on a rack in a box or room having double sides filled with non- 


conducting material, and metallic pans containing ice and salt 
were set over the fish, and the whole inclosed. The temperature 
in the room would soon fall to several degrees below the freezing 
point of water, and in about twenty-four hours the fish would be 
thoroughly frozen. The fish were then covered with a coating 
of ice^by immersing them a few times in ice cold water, forming 
a coating about j4-i"ch in thickness, after which the fish were 
wrapped in cloth, and a second coating of ice applied. In some 
instances they were covered with a material somewhat like gutta 
percha, concerning which much secrecy was exercised. The 
fish were then packed closely in another room well insulated 
against the entrance of warmth, and in which were a number 
of perpendicular metallic tubes, several inches in diameter, filled 
with a mixture of ice and salt to keep the temperature below the 
freezing point. 

The process was also patented in the Dominion of Canada, 
and a plant was established at Bathurst, New Brunswick, in 
1865, the output consisting almost entirely of salmon, a large 
proportion of which were imported into the United States. In 
order to hold the frozen fish in New York, while awaiting a 
market, Piper constructed a storage room in a shop on Bcckman 
street, that being the first cold storage room for fish in the United 
States. The walls of the room were well insulated, and around 
the sides were two rows of zinc cylinders, ten inches in diameter 
at the top, and decreasing in size toward the bottom, connecting 
at the lower end with a drainage pipe. The cylinders were filled 
with a mixture of ice and salt, which was renewed whenever 
necessary. Whatever may have been the imperfections in his 
process of freezing, the system of storage was quite satisfactory, 
and diflfers little from that in use at the present time. Piper re- 
fused to sell rights to others for the use of his process, and after 
maintaining a monopoly of the business for three or four years 
his exclusive right to it was successfully contested by other fish 
dealers in New York, who applied it to storing other fish besides 

The principal objection to Piper's process is that the fish 
are not in contact with the freezing mixture during the opera- 
tion of freezing, and, consequently, too much time is required 
for them to become thoroughly frozen. Several devices have 




been used for overcoming this objection, among which are cover- 
ing the fish with thin sheet rubber or other waterproof material, 
and packing them in the mixture of ice and sah. 

The greatest improvement, and the one used almost ex- 
clusively when ice and salt form the freezing agency, originated 

FIG. I.- 


in 1868 with Mr. William Davis, of Detroit, Mich., the descrip- 
tion being as follows : Two thin sheet metal pans are made to 
slide one over the other, the object being to place the fish in one 


pan, slide the other pan vertically over it, and the box is then 
placed in direct contact with the freezing mixture. By having 
the box constructed in this manner, it is capable of being ex- 
panded or contracted to accommodate the size of whatever may 
be placed therein, and the top and bottom always be in contact 
with the articles to be frozen. After the fish are inclosed in the 
pans, the latter are placed in alternate layers with layers of the 
freezing mixture between and about them. When the fish are 
thoroughly frozen they are removed from the freezing pans and 
placed in a cold storage chamber at lo*' or 12*^ F. below freezing. 
As the trade developed the size of the storage rooms in- 
creased and improvements were adopted in the arrangement and 
form of the ice and salt receptacles, and in the method of handling 
the fish. But the freezing with pans immersed in ice and salt, 
as in the Davis process, and the subsequent storage in the manner 
used by Piper, continued without great modification until the 
introduction of mechanical refrigeration into the fishing trade 
in 1892. At that time ice and salt freezers and storage rooms 
existed at nearly all the fishing ports on the great lakes ; eight or 
ten small ones were in New York City, and several were in use 
on the New England coast. Some of those on the great lakes 
were quite large, with storage capacity of 700 or 800 tons or 
more, and the aggregate capacity of all in the country approxi- 
mated 8,000 tons. Cold storage houses fitted with ammonia 
machines had been established at various places along the coast 
and in the interior during the ten or 'fifteen years preceding, 
and in these some frozen fish had been stored. But the first 
establishment using a refrigerating machine for freezing fish ex- 
clusively was erected at Sandusky, Ohio, in 1892.- The method 
of freezing in these establishments diflFcrs from the ice and salt 
process in- that the pans of fish are placed on and between tiers of 
pipes carrying cold brine or ammonia instead of being immersed 
in ice and salt. In the storage rooms less difference exists, coils 
of brine carrying pipes taking the place of the ice and salt re- 
ceptacles, the blocks of fish being removed from the pans and 
stored as in the older process. 


The outfit of an ice and salt freezer consists principally of 
temporary stalls or bins where the fish are frozen, and insulating 


rooms where the frozen fish are stored at a low temperature. 
In addition to these there are ice houses, salt bins, freezing pans, 
and the various implements for the convenient prosecution of 
the business. The freezing bins are usually temporary struc- 
tures within the fish house, and are generally without insulation. 
The walls of the fish house may form the back, while loose boards 
are fitted in to form the sides and front as the bin is filled, in the 
manner hereafter described. A better way is to construct the bin 
with permanent sides and back four or five inches thick, fitted 
with some non-conductor, with double or matched floor, and with 
movable front boards. 

The storage rooms are commonly arranged in a series side 
by side and separated from each other by well insulated parti- 
tions tlie capacity of the rooms ranging from 25 to 250 tons each. 
The outer walls of these rooms, as well as the floors and ceilings, 
are well insulated, made usually of heavy matched boards, with 
interior packing of some non-conductor of heat, such as planing 
mill shavings, sawdust, pulverized charcoal, chopped straw, rock 
wool, slag wool, etc. Most of the walls are sixteen or eighteen 
inches thick, filled with planing mill shavings or sawdust, and 
in some freezers the damaging eflfect of rats is obviated by plac- 
ing linings of cement between the shavings and the board walls. 
Most of these loose materials have their economic drawbacks, 
chiefly because of their strong hygroscopic tendency, the material 
losing its insulating power and decaying, this decay also attack- 
ing the wood of the walls. Because of this, many of the storage 
rooms recently constructed are insulated by having the walls 
made up of a combination of rock or mineral wool, insulating 
paper, air spaces and inch boards. 

The sides, and in some cases the ends of the room, are lined 
with the ice and salt receivers, consisting of galvanized -sheet iron 
tanks, eight or ten inches wide at the top, narrowing to three or 
four inches at the bottom, and placed about four inches from the 
wall in order to expose their entire surface to the air in the room. 
These tanks open at the top, which extends above the ceiling, so 
that they may be filled without opening the storage rooms. At the 
bottom is usually a galvanized iron gutter, into which the water 
resulting from the melting ice flows, whence it is conducted 
through the floor of the room by a sliort pipe, protected from 


the entrance of air at its lower end by a small drip cup, into 
which the brine falls and runs over at the top. The ice and salt 
tanks must be cleaned from time to time in order to rid them 
of dirt and sawdust. Their capacity should be in proportion to 
the size of the room and the excellence of the insulation, and 
they should be large enough to render it unnecessary to fill them 
oftener than once a day, even in the warmest weather. 


In the freezing houses using mechanical refrigeration there 
is, as customary with cold storage houses used for other products, 
a machinery room containing the boilers, compression pump or 
absorption tank, according to the system employed, brine pump, 
etc. Apart from these, and within well insulated walls, are the 
cold rooms, of which there are two kinds, one for the freezing of 
fish and the other for their storage after being frozen, the capacity 
of the latter being usually much greater than that of the former. 
In the freezing room the circulating pipes containing the cooling 
material are one-half inch to two inches in diameter, and ar- 
ranged in shelves or nests with horizontal layers four or five 
inches, and sometimes ten inches apart, ranging from the floor 
to the ceiling, the entire room being occupied with these nests, 
except sufficient space for moving about. The temperature de- 
pends, of course, on the quantity of green fish and the progress of 
the freezing process; but with direct expansion, or using brine 
made of chloride of calcium as the circulating medium, a tem- 
perature of — io° F., or less, is obtainable. In this room the 
fish are frozen, and then they are removed to the storage rooms. 
These are constructed similarly to the storage rooms in ice and 
salt freezing houses, the only diflference being that brine carrying 
pipes are substituted for the ice and salt receptacles. The pipes 
in the storage rooms are usually larger, but are not so numerous 
as in the freezing room. They are arranged at the ceiling, and 
sometimes about the upper side walls also. 

In freezing fish, as in preserving most food products, close 
attention must be given to the economy of the process as well as 
to the excellence of the product, and the expense of the best proc- 
ess frequently prevents its use. To secure the best results, the 
stock to be frozen should be perfectly fresh and free from bruises 


and blood marks. It improves the appearance, and therefore 
increases the value, if the fish are graded according to size, but 
this is rarely done. All kinds of fish keep and look best when 
frozen just as they come from the water, with heads on and 
entrails in, and it is better that the fish be not eviscerated before 
freezing, except in case of very large fish, such as sturgeon. 
But since the freezers receive the surplus from the fresh fish 
trade, many have been already split and dressed. Generally, fish 
that are frozen with heads oflf and viscera removed are not 
strictly fresh, but this rule has several exceptions. 

Whether round or eviscerated, the fish are first washed by 
dumping them into a wash box or trough containing fresh cold 
water, which is frequently renewed, and stirring them about 
with an oar-shaped paddle or cloth swab, to remove the slime, 
blood, etc. Some freezers consider it inadvisable to wash flat 
fish, because of their being too thin. From the wash box the 
fish are removed by hand and placed in the pans in such a manner 
as to make a neat and compact package entirely filling the pan, 
so that the cover will come in contact with the upper surface of 
the fish. It is desirable, when the size of the fish so admits, that 
the bellies be placed upward, since that portion has greater ten- 
dency to decompose, and, as the cold passes down, this arrange- 
ment results in freezing the upper portion of the block first, and 
also in less compression of the soft portion of the fish by remov- 
ing the weight therefrom. It is also desirable to have the backs 
of the fish at the sides of the pan and the heads at the ends, so 
as to protect the blocks in handling, but this is by no means a 
uniform practice. In case the fish have been split and eviscerated 
it is desirable to place them slanting on the sides, but with backs 
up, so as to permit the moisture to run from the stomach cavity. 
Some freezers place herring and other small fish on their sides, 
two layers deep in the pans, while others place a bottom layer 
of three transverse rows, the end rows with the heads to the 
edge of the pan, and a top layer of two transverse rows laid in 
the two depressions formed between the bottom rows. In case 
of pike and some other dry fish a small quantity of water is 
sprinkled over them, since they do not ordinarily retain sufficient 
moisture to hold together when frozen, as is the case with most 
species. As soon as the pans have been filled and the covers 


fitted on they are placed in the sharp freezers, which have been 

In those houses using ice and salt as the freezing medium 
the arrangement of the ice, salt and fish pans is as follows : The 
ice, after being passed through a grinder, where it is crushed into 
small particles, is mixed with salt in the proportion of from 
eight to sixteen pounds of salt to one hundred pounds of ice. 
The mixing is most conveniently done by scattering salt over each 
shovelful of ice as the ice is shoveled from the grinder to a 
wheelbarrow. Many varieties of salt are used, most houses pre- 
ferring a coarse mined salt because of its cheapness. Others 
use finer salt because it comes into closer contact with the ice and 
results in a lower degree of cold and the more rapid freezing of 
the fish, although the mixture does not last as long. 

The amount of ice and salt required in freezing a given 
quantity of fish depends principally on the fineness of the ma- 
terials and the proportions in which they are used, and to a less 
exfent on the outside temperature, the amount of moisture in 
the atmosphere, the size of the pans and the manner in which 
the fish are placed therein. The finer the ice and salt, the quicker 
the freezing and the consumption of the ice. A larger proportion 
of salt results also in quicker freezing. The most economical 
quantities appear to be about eighty-five pounds of salt and i,ooo 
pounds of ice to each i,ooo pounds of fish, although some freezers 
use much more salt and less ice. Much larger quantities of ice 
and salt are required during warm weather, and more is neces- 
sary also when the atmosphere is moist than when it is dry. 
Some of the ice and salt generally remains unmelted, and this 
may be used over again in connection with fresh materials, addi- 
tional salt being mixed with it ; and as it is weaker than new 
ice it should be used mainly at or near the bottom, the top of 
the pile taking care of the bottom, since the cold descends. 

In making the freezing pile, an even layer of ice and salt, 
about three or four inches deep, is placed at the bottom, on which 
is laid a tier or layer of pans filled with fish, about three inches 
of ice space intervening between the pans and the sides of the 
bin. This is followed successively by a layer of ice and salt 
about two or three inches deep, and a layer of pans, the surface 
of each layer of ice being made even and smooth by means of a 


straight edge. Sideboards are placed as the height of the pile 
requires, and a wide board laid on the pile furnishes a walk for 
the workmen in placing the freezing mixture and the pans. Some 
freezers place the pans in double tiers between the layers of ice 
and salt, and in this case the thickness of the layers of freezing 
material must be increased. In some freezers a light sprinkling 
of salt is thrown on top of the pans as they are successively 
placed. The pile is built up as high as it is convenient for 
handling the pans of fish, which usually does not exceed six feet. 
A double quantity of the freezing material is put on top, and 
the whole should be covered with wood or canvas to exclude 
the air. The fish are usually frozen completely in about fifteen 
or eighteen hours, but they usually remain in the pile until the 
following morning, when they are ready to be placed in cold 


Being moist, the fish are frozen solidly to each other and 
to the surfaces of the pans while in the sharp freezer. To remove 
them from the pan the latter is usually passed for a moment 
through cold water, which draws the frost sufficiently from the 
iron to allow the fish to be removed in a block without breaking 
apart. In one or two freezing houses the thawing of the fish 
from the sides of the pan is omitted, the cover being loosened and 
the block of fish removed by striking the pan at the ends and 
sides, after which the block of fish is dipped for a moment in 
cold water. 

Considerable moisture adheres to the fish from its being 
dipped in water, and this being frozen by the surplus cold forms 
a coat of ice about one-fiftieth inch thick, entirely surrounding 
the irregular block. The process of freezing dries the fish to 
some extent, the loss in weight amounting to about 2 per cent, 
but the ice coating adds about 4 per cent to the weight. 

After the coating of ice has been applied, the fish are passed 
to the cold storage room, where they are arranged in neat piles, 
the blocks being placed vertically in some instances; but more 
frequently they arc arranged horizontally in piles extending from 
the floor nearly to the ceiling. Strips two or three inches thick 
are laid on the floor to keep the fish slightly elevated, and allow 
the cold air to circulate underneath. 


The quantity of ice and salt required in the establishments 
which use those materials in the storage rooms is dependent on 
the outside temperature and the excellence of the wall insulation, 
and is independent of the amount of frozen fish in the room, 
requiring no more freezing material to keep fifty tons of frozen 
fish at an even temperature than to keep two tons in a room- 
of equal size. With 1 6-inch or 1 8-inch walls, well insulated, 
it requires the melting of about forty pounds of ice per day for 
each IOC square feet of wall surface when the outside tempera- 
ture is 60° F., to maintain a temperature of 18° F. inside, this 
calculation leaving the opening of doors and the cooling of fresh 
material out of consideration. The temperature in the storage 
room should be constant, and about 16° or iS*' F. is considered 
the most economical. Above 20° F. the fish are likely to turn 
yellow about the livers, a result generally attributed to the burst- 
ing of the *'gall." 

The storage rooms should be free from moisture, since the 
latter oflfers a favorable place for the settlement and development 
of micro-organisms of all kinds, which tend to mold the .fish. 
To reduce excessive moisture, a pan of unslaked lime, chloride 
of calcium or other hygroscopic agency, may be placed in the 
room, the material being renewed as exhausted. If the storage 
rooms are very moist, they should be dried out before storing 
fish in them, this being readily accomplished by using a small gas, 
coke or charcoal stove. The storage rooms cooled by refrigerat- 
ing machines may be dried by passing hot water through the 
pipes, which, of course, should, under no circumstances be done 
when there are fish in the rooms. In case of mold appearing 
on the fish, it might be well to try spraying them with a solution 
of formalin, consisting of ten parts of formalin and ninety parts 
of water, which should be used at the first sign of mold. 


All fish deteriorate to some extent in cold storage, depreciat- 
ing both in flavor and firmness. The amount of this decrease 
is dependent primarily on the condition of the fish before freez- 
ing and the care exercised in the process of freezing, and, sec- 
ondarily, on the length of time they remain in cold storage. The 
loss in quality during storage is due principally to evaporation. 


which begins as soon as the fish are placed in storage, and in- 
creases as the ice coating is sapped from the surface. 

Evaporation proceeds at very low temperatures, though not 
so rapidly as at higher ones ; even at a temperature of o° F. the 
evaporation during two or three months is considerable. The 
• heavier the ice coating the less the evaporation ; but it is almost 
impracticable to entirely prevent it, and under ordinary condi- 
tions it amounts to about 5 per cent in weight in six months, but 
the loss in quality is greater than the loss in weight. 

The most practicable method of restricting evaporation, 
other than coating with ice, is to wrap the fish in waxed or parch- 
ment paper and place them in shipping boxes, whose length 
and width are slightly greater than the blocks and deep enough 
to contain four or five blocks, or 120 to 150 pounds of fish. 

Along the great lakes the most popular fish for cold storage 
are whitefish, lake trout, lake herring, blue pike, saugers, stur- 
geon, perch, wall eyed pike, grass pike, black bass, codfish and 
eels. In addition to these species, the great lakes freezers receive 
large quantities of blue fish and squeteague (sea trout) from the 
Atlantic. On the Atlantic coast bluefish, halibut, squeteague, 
sturgeon, mackerel, flat fish, cod, haddock, Spanish mackerel, 
striped bass, black bass, perch, eels, carp and pompano are frozen. 
Salmon, sturgeon and halibut are the principal species frozen on 
the Pacific coast. 

Some varieties of fish are so very delicate that it is not 
deemed profitable to freeze them, especially shad, but even these 
are frozen in small quantities. Oysters and clams should never 
be frozen, the best temperature for cold storage being 35° to 
40° F., and when stored in good condition they will keep about 
six weeks. As an experiment they have been kept twelve weeks, 
but storage for that length of time is not advisable. Caviar also 
should never be frozen, but held at about 40° F. Scallops and 
frogs* legs, however, are frozen hard in tin buckets and stored 
at a temperature of 16° to 18° F. Sturgeon and other fish too 
large for the pans are frequently hung up in the storage rooms 
by large meat hooks, and when frozen are dipped in cold water 
and stored in piles. 

In some of the largest freezing houses on the Atlantic sea- 
board, which freeze and store fish as well as other food products. 


the fish to be frozen are simply hung up in the sharp freezer, the 
heads being forced on to the sharp ends of wire nails protruding 
from cross-laths arranged in series. After the fish are frozen 
they are removed and piled in storage rooms, where the tempera- 
ture is from 15° to 18*^ F. When the handling of fish is of 
minor importance compared with other food products, they are 
generally placed on slat-work shelves in either a special freezing 
room or in a storage room where the temperature is kept below 
20^ F., or they are retained in bulk in baskets, boxes or barrels 
in the same room. But these methods are not productive of 
results even approximating those in the great lakes freezers. 

The cost of cold storage and the deterioration in quality 
make it inadvisable to carry frozen fish more than nine or ten 
months, but sometimes the exigencies of trade result in carrying 
them two and even three years. In the latter case they are 
scarcely suitable for the fresh fish trade unless the very best of 
care has been exercised in the freezing and storage, and it is 
usually better to salt or smoke them. 

The rate of charges in those houses which make a business 
of freezing and storage for the general trade is usually from a 
half cent to one cent for freezing and storage during the first 
month, and about half of that rate for storage during each sub- 
sequent month, depending on the quantity of fish. However, the 
cost of running a first-class plant at its full capacity is probably 
less than one-third, or even one-fourth, of the minimum above 
quoted, since it costs no more to run a storage room full of fish 
than one-fifth full. 




The use of refrigeration for the protection of furs, fur and 
woolen garments, rugs, carpets, trophies, fine furniture, etc., 
against the ravages of moths or carpet beetles is comparatively 
recent, and prior to the year 1895 no business of consequence 
was done in this line. Now many of the larger household goods 
warehouses, and some of the regular cold storage houses, have 
rooms devoted to this purpose, and several large concerns, both in 
America and Europe, are operating refrigerating equipments 
exclusively for the preservation of furs and fabrics. 

The use of cold storage for this line of goods is not as yet 
fully or even moderately developed. The prejudice of furriers 
is largely responsible, and wherever the cold storage manager 
endeavors to obtain business in this line, he usually has a strug- 
gle with the furrier. The time honored method of caring for 
furs, etc., during the heated term, has been to periodically beat, 
brush, comb or treat them with various chemicals or liquids for 
the purpose of destroying or preventing the hatching of the egg 
which produces the larva; of the destructive miller and beetle. 
These pests are very generally known as moths. The care of 
fnrs during the hot weather of summer has been one of the 
sources of the furrier's income during his dull season. Natur- 
ally, therefore, he looks upon any new method of protecting furs 
with suspicion and in an unfriendly light. 

In nearly every instance where the author has obtained the 
experience of warehousemen on this subject, the same conditions 
prevail. In some instances where cold storage is largely in use 
for this purpose, it has been introduced by interesting a promi- 
nent local furrier, and making concessions which would attract 
his business. This furnishes the cold storage warehouseman 
with a good reference. After acquiring such a customer, busi- 



ness should be solicited by distributing attractive descriptive ad- 
vertising matter from house to house. A number of warehouses 
known to the author have secured their business almost wholly in 
this way, and without help of local furriers. It is only a question 
of time when the prejudice of furriers will be overcome, and they 


will become the heaviest customers of the cold storage house; but, 
for the present, their preconceived ideas and fancied financial in- 
terests make them the competitors, to a great extent, of the cold 
storage house. 

Foot for foot, the storage of furs and fabrics pays better 
than any other class of goods, and cold storage houses located 



in or near the residence portion of cities, in latitudes wh^re furs 
are worn, should make an effort to obtain this business. The 
detail of looking after it is considerable, but it works in nicely 
with other business. So far the business has been largely 
developed by the household goods warehousemen, and at present 


the largest and most successful businesses in this line are con- 
ducted by such houses, chiefly because these already have a 
clientage from whom to draw business, and are equipped with 
facilities for collecting and delivering goods. To the warehouse- 
man who handles both household goods in dry storage and per- 
ishable goods in cold storage, the setting aside of a room for 



the purpose is a comparatively inexpensive experiment, and it 
may result in a good business. The largest and most successful 
houses handling these goods have fireproof buildings. The large 
value stored in a small space makes the fireproof building es- 
pecially adapted to this class of goods. 

The correct temperature for a fur and fabric room has not 
been accurately determined as yet. Rooms are in operation rang- 
ing in temperature from 15° to 40° F. It has been demon- 
strated that a temperature of 40° F. will prevent the operation of 


damaging larvae, but does not destroy them. A safe working 
temperature for the cold room would be anywhere between 25° 
and 35° F., and it is believed that the latter temperature is amply 
low, if continuously maintained. 

Raw silk has been placed in cold storage for other reasons 
than to prevent the working of damaging moth. When stored 
at ordinary temperatures a loss of weight and lustre results, 
caused by the evaporation of the natural moisture and volatile 
matter contained in the silk. A temperature below 30° F. pre- 
vents the evaporation and maintains the lustre. Inferior grades 



are especially liable to damage when exposed on the shelves for 
a time and cold storage is necessary to a successful holding. 

Furs and fabrics should not be stored in a room with goods 
giving off moisture, as at times the moisture in such a room may 
be excessive and harm result. A room containing nothing but 
furs will be comparatively dry, because furs do not give off 
moisture, and the only source from which moisture may be 
added to the air of the room is by air leakage, opening doors, 
and the exhalation from persons working in the room. A well 


insulated fur room, protected by a properly designed air lock or 
corridor, is so dry that the pipes rarely show white, the coating 
of frost is so very light. It has been advanced as a theory that 
a very low temperature, like say zero or 10° F. above, would be 
detrimental to the skins or leather of furs, causing them to dry 
out. Evaporation is caused by a low relative humidity, entirely 
independent of temperature, so this theory is not tenable. (See 
chapter on "Humidity.") The average humidity during winter, 
when furs are in use, is much lower in most localities where furs 
are worn than that of a cold storage room under ordinary con- 


ditions. Xo data are at hand regarding the humidity at which 
fur rooms should be carried, but it is no doubt lower than for 
goods which throw off moisture; that is, the room should be 
dryer. It may happen that furs removed from a refrigerated 
room and taken into a comparatively warm atmosphere will 
show dampness on their outer surfaces. This is not from any 
fault of the storage room, but because the moisture is condensed 
from the warm air upon the cold surface of the goods. This 
may be avoided by packing the goods inside the cold storage 


room in tight boxes before delivery, so that the goods will be 
warmed slowly and condensation prevented. If furs and fabrics 
are kept in a room by themselves, no harm will result from the 
moisture, unless conditions are radically wrong. If, when re- 
moved from storage, goods show a condensation of moisture, 
they should be thoroughly aired until dry before delivering, by 
placing where a gentle current of air will flow over them, as cus- 
tomers may think the moisture was caused by some defect in the 
system of cold storage. 




The forced air circulation system is particularly applicable 
to the storage of furs and fabrics, and it is recommended, not 
especially as a matter of purifying the rooms or producing 
greatly improved conditions, but as a means of avoiding the use 
of cooling pipes, placed directly in the rooms. Pipe coils on 
the walls or ceilings of a room may drip at times and cause a 
spattering of water, which will damage the goods. Space will 
also be saved, which is an important item, especially in expen- 
sive fireproof warehouses. The accompanying illustrations of 
rooms used for fur storage show clearly the large space occupied 




by piping. It is not only the loss of space actually occupied by 
the pipes, but also that the goods must be stored at a safe dis- 
tance from them. Thoroughly distributed circulation of air is 
not essential when using the forced circulation system for furs; 
all that is necessary is a distribution of air which will produce 
uniform temperatures. A cross-section of the ducts arranged in 
a fur room designed by the author is .shown in diagram. The 
perforations in these ducts are on the sides of the flow and re- 
turn ducts. No marked difference in temperature can be noted 
in different parts of the room when the fan is kept in continuous 
operation. This arrangement of air distribution is not reconi- 



mended for any goods which throw off moisture, but is sufficient 
for furs and fabrics. The first rooms to be used exclusively for 
the storage of furs and fabrics were equipped with brine piping 
directly in the room, and such an arrangement is still largely in 
use, but the forced circulation or indirect system outlined above 
is rapidly coming mto use. 

The ventilation of fur rooms may be easily accomplished; 
and while not absolutely necessary to the welfare of the goods. 


it is much better to have a nice sweet smelling room to show 
prospective customers than one which has the lifeless and impure 
atmosphere encountered in some fur rooms. The warm weather 
ventilating system invented by the author for use in summer is 
desirable at frequent intervals. (See chapter on "Ventilation.'') 
At one of the houses designed by the author a quantity of cloth- 
ing containing moth balls was received, and the fact was not 
discovered imtil the room was well scented. A few hours' opera- 



tion of the warm weather ventilating system was sufficient to 
sweeten the air of the room perfectly. The rooms may be blown 
out and thoroughly ventilated by forcing in fresh cold air from 
the outside by using the cold weather ventilator in winter. 

One of the first difficulties of the cold storage manager is 
to educate his customers to do away entirely with the use of 
moth balls, camphor balls, tar camphor, carbolic camphor, pow- 
ders, tar paper or any of the ill smelling trash of various kinds 


which has for years been used to keep out the damaging moths. 
Some warehousemen have also been troubled by the stable odor 
from robes and coachmen's garments. Goods received containing 
these objectionable odors should be carefully aired for some days 
before placing in the cold storage room. If the odors cannot be 
eradicated, the goods must be isolated in a room by themselves, 
or rejected for storage and returned to the owners. It should 
be the warehouseman's study to return goods in as good or better 


condition than when received. To this end, all objectionable 
goods must be excluded from the storage rooms. 

The services of an expert furrier are provided in some 
cases, and where the volume of business is sufficient, one may be 
regularly employed. Any bright young man may be trained to 
inspect furs on arrival at the storage house. Any blemishes or 
imperfections should be noted on the receipt given to the cus- 
tomer as a protection to the warehouseman. All furs should be 
carefully beaten, dusted and aired before placing in the refrig- 
erated rooms, and properly placed or stored to keep them in the 
best possible condition. 

Trophies like stuffed animals, heads, skins, etc., are best 
hung or laid on racks. The best method of storing coats, cloaks, 
etc., is to hang them on forms or shoulder stretchers to preserve 
the shape and hang of the garment. If any metal hooks with 
shoulders are used they should be wrapped with tissue paper 
to prevent discoloring light colored furs or garments. The forms 
are suspended from racks, and the whole covered by a piece of 
heavy unbleached sheeting. This arrangement is plainly shown 
in the accompanying view of a cold storage room (Fig. 8). The 
illustrations (Figs, i to 9) also show the method of storing fur 
rugs, stuffed heads, carpets, trunks, etc. In some cases each 
individual garment is encased in a separate cloth cover. Sepa- 
rate closets are sometimes provided for the use of single indi- 
viduals, furriers and large customers, or for the storage of 
especially valuable garments, the keys to which may be carried 
by the customer. Such closets are usually made of slat or open 
wire work, to allow of a free circulation of air. 

A few of the advantages of refrigeration for the protection 
of furs and fabrics are here concisely stated for the benefit of 
those preparing printed matter for distribution : 

Cold is instrumental in the production of furs, and it is as necessary 
to their preservation. 

Cold develops and enriches the fur when on the animal's back and 
preserves its color and gloss when manufactured into useful coverings. 
Cold storing is like putting the fur back into its native clement. 

• Cold prolongs the life of the fur by retaining the natural oils, which 
are evaporated by the hot, dry air of summer. 

Not only is the appearance of the fur improved, but the flexibility 
and softness of the leather which supports it are retained. 

Carpets, rugs and other woolens lose color and life in the hot sum- 
mer air. A cold atmosphere revives the colors and rejuvenates' the fiber. 


The wear and tear on furs, carpets and rugs by excessive beating is 
entirely eliminated. 

Garments stored on forms in refrigerated rooms are ready for imme- 
diate use ; in fact, can be removed from cold storage, worn for a single 
night, and returned. 

Curtains or draperies may be suspended from racks, avoiding damage 
from folds. 

Furriers who have used the system heartily indorse it 

Obnoxious odors from use of moth preventives are avoided. 

Cold storage rooms are dust proof. 

Cold storage gives absolute security against moth. 

The usual storage rates for fur and fabric cold storage arc 
given below. The prices are in some cases less, in fact, some- 
times only one-half those given. Each warehouseman must 
be governed by local conditions and competition, and in most 
cases the charges made by the furrier under the old method must 
be approximately met. A furrier's charges nearly alw^ays in- 
clude a guarantee against fire and moth. 


Muffs $0.75 to $1.00 

Boas, caps or gloves 75 to i.oo 

Collarettes i.oo to 1.50 

Capes not exceeding 20 in. in length i.oo to 1.50 

Capes or sacques not exceeding 24 in. in length i.oo to 1.50 

Capes or sacques not exceeding 28 in. in length 1,50 to 2.00 

Capes or sacques not exceeding 36 in. in length 2.00 to 2.50 

Garments, such as dolmans, long sacques, etc 1.50 to 2.50 

Overcoats, etc., not exceeding 40 in. in length 1.50 to 2.50 

Garments exceeding 40 in. in length 2.00 to 3.00 

Lap robes 1.50 to 2.50 

Rugs, according to size i.oo and up 

Stuffed animals, birds, mounted heads, etc i.oo and up 

Monthly rate, one-third of season rates. 

Season, nine months. 


Woolen garments stored in same manner as fur garments', two-thirds 
of fur rates. 

Blankets, clothing or other garments stored in trunks or boxes, rate 
of seven cents per cubic foot per month, or fifty cents per cubic foot per 
season of nine months. 

Carpets and rugs not in boxes or trunks, four cents per cubic foot 
per month. 

Suits and dress suits, $1.50 per season. 

I^'urniture, forty cents to sixty cents per cubic foot per season. 

Monthly rate, one-third of season rate. Season, nine months. 

Some warehouses make the season only six months, but the 
usual season is nine months, and in most cases is figured to end 
January i. Goods carried beyond January i are usually charged 
for at a short season (/. e,, January i to April i) rate, at one- 


third the long season rate. It is customary for warehousemen to 
make a rate which insures against fire, moth and theft, although 
this is by no means a imiversal rule.* When so done the usual rate 
is I per cent per season on valuation, insurance rate to govern 
to some extent. 

The form of warehouse receipt here shown has been found in 
practice to answer the purpose for furs, etc., very well, but is 
subject to many limitations and modifications. The words "Not 
negotiable" should be printed or stamped across the face of the 
receipt. It need not necessarily take this form, but should in- 
clude the items mentioned and should read somewhat as follows : 


100 Main Street. 

No New York, 190.^. 

RECEIVED for the account of 


(contents of packages imknown), to be stored in cold storage, for which 
the sum of dollars paid to this com- 
pany for storage from the date hereof until 

The responsibility of the company for any piece or package, or the 
contents thereof, is limited to the sum of one hundred dollars, unless the 
value thereof is made known at the time of storing, and receipted for in 
the schedule. An additional charge will be made for a higher Valuation. 

In consideration of the additional sum of dollars, the 

said A'rrt' York Fur and Fabric Siora<{c Co. agrees to protect the said 
articles from loss or damage by moths, fire and theft. 

Should the above goods be withdrawn before the expiration of the above 
term of storage, no portion of the charge shall be remitted, and, if con- 
tinued longer, it shall be deemed a renewal under the same conditions, for 
which a like rate shall be chargeable. 

The said goods are hereby valued, for the purpose of insurance, at 

the sum of 


When the property covered by this receipt is zviihdraivn, this receipt 
should be surrendered to the company. 

, Supt. 

This chapter would not be complete without the addition of 
an extract from the article on the "Cold Storage for Fabrics," 
by Dr. Albert M. Read, of the American Security and Trust Co., 
Washington, D. C, published in full in the June, 1897, issue of 
Ice and Refrigeration. Dr. Read has taken up the subject and 
handled it in a masterly and exhaustive wav. Credit i< also 



due to Walter C. Reid, of the Lincoln Safe Deposit Co., New 
York, and Albert S. Brinkerhoff, of the Utica Cold Storage and 
Warehouse Co., Utica, X. Y., for assistance in securing much 
of the information contained in the foregoing. Following is a 
portion of Dr. Read's article, referred to : 


In order to conduct our business intelligenily, it became necessary 
to ascertain the effect of low temperatures upon the moth and beetle 


in the various forms of egg, larvae and perfected insect. We, therefore, 
had a small room fitted with brine pipes, divided into several sections by 
stop-cocks, so that the temperature could be controlled to within about 
5°. and began operation at from 20° to 25'' F. When we thought we had 
exhausted the subject at these temperatures, we took the next in order, 
from 25° to 30° F, and progressed in this manner upward until the tem- 
peratures of from 50° to 55° F. were reached. Each of these tests neces- 
sarily consumed considerable time, the series having occupied the full 
period of two years. Early in the first year, however, we learned that 
the line of safety lay somewhat higher than the freezing point (^2°)f 
and our plant was run for the balance of the season at that temperature. 


The Egg. — It is probable that the egg of the motli and beetle requires 
a temperature somewhat higher than 55** F. for hatching. I say probably, 
because, owing to the difficulty of obtaining the eggs, my experiments on 
them have not been sufficiently numerous to allow of positive conclusions, 
although those that have been made point strongly to the possibility stated. 

The Larvae. — The larval condition is the one in which all the damage 
to fabric is done by the insects in question. In passing from the egg 
through this condition to the perfected insect, the fiber of the wool, fur, 
etc., is eaten by the larvae of both the moth and the beetle for the grease 
and animal juices in it, these constituting the principal source of food, 
and by the larva of the moth for material out of which to spin the web 
that constitutes a large proportion of the cocoon used for its protection. 
In the larval state it was found that any temperature lower than 45° F. 
was sufficient to keep the insect from doing damage to fabric, although 
at that temperature, and at a temperature as low as 42° F., there was slow 
and sluggish movement of the animal. At temperatures below 40° F. 
movement was suspended, and the larva became dormant. At tempera- 
tures above 45° F. the movements of the larva became active, and it began 
to work upon the fabric, the amount of this work and the quickness of 
movement increasing with each <legree of temperature up to 55° F., when 
the normal condition of activity appeared to be reached. 

• The Perfected Insect. — The miller and beetle, when subjected to 
temperatures below 32° F.. were soon killed, as they were also after a 
longer time at ail temperatures between that and 40° F. At temperatures 
between 32° and 40° F.. however, when the insects were placed in the 
center of a roll of heavy woolen rugs, they appeared to enjoy an immunity 
from death for several weeks, although during this period they were 
entirely dormant. 

It will bo seen from the above that the investigations made have 
quite conclusively proven that cold storage rooms for the preservation of 
furs and fabrics from the ravages of moth and beetle may be kept at a 
temperature as high as 40° F. with perfect safety, so far as these insects 
are concerned. There may, in some plants, however, be trouble from 
the drip from the cooling pipes of the storage room at this temperature, 
which will, of course, be very objectionable, and should be obviated by 
a slight lowering of the temperature of the room. We have run our 
rooms at temperatures varying from 35° to 40° F. without trouble in 
this regard. 

In the course of the investigation some matters of interest in con- 
nection with the effect of cold upon these insects came to my notice. As 
those may -prove of value in the future. I will state them in a few words. 
It was found that the larvae of both the moth and the beetle had the 
power of resisting temperatures as low as 18° F. for a long period without 
apparent harm, and that they came out of the dormant condition super- 
induced by the low temperature in the same physical condition as* when 
they entered it, and apparently took un their natural avocation at the 
precise point where it was interrupted. When these larvae were alternately 
exposed to low and higher degrees of temperature, so that they passed 
from the dormant to the active condition and back again several times 
in succession, their power of resistance was considerably lessened, and 
they died much sooner than \vhen kept dormant in a low temperature 
continuously. This would indicate that a winter, during which short 
periods of cold are followed by similar periods of warm weather, would 
be followed by a summer of decreased in<;ect life. 




The care of cold storage rooms during periods of idleness, 
or when no goods are in storage, is of the greatest importance 
for the reason that good results in storage of goods depend 
largely on the condition of the storage room. With this fact in 
mind the author sent out a circular letter of inquiry to a number 
of cold storage warehousemen containing a list of questions 
which embrace the subject of whitewashing: whether it should 
be done by hand or machine; whether any other preparation is 
as good as whitewash; whether it would properly purify rooms 
for the storage of such goods as eggs after storing apples or 
other fruits ; whether it is necessary to whitewash each year and 
also in regard to painting, at the time of whitewashing, the pipes 
or refrigerating surfaces which cool the room. Questions were 
also asked in regard to the methods of preparing whitewash and 
whether means of ventilating are provided at the time of white- 
washing. Further information of a general character was so- 

The nimiber of replies received was rather disappointing, 
but some of the more careful and conscientious cold storage men 
gave detailed and very full information. It is evident from a 
majority of the answers received that comparatively little atten- 
tion is given to the cold storage rooms when they do not contain 
goods. Cold storage rooms need as careful attention, although 
in a different way, when they do not contain goods, as when 
goods are stored therein. When the flow of refrigerating me- 
dium (usually ammonia or brine) is shut off at a time when there 
is frost on the pipes, this frost will evaporate in the form of air 
moisture, even though it does not actually melt, andjrause the 
air of the room to become damp. Dampness with a compara- 
tively high temperature will in time cause a growth of mold and 


a musty condition of the room. Systematic whitewashing with 
ventilation will kill this growth of mold, but it is much better to 
prevent a trouble of this kind than to overcome it after it has 
obtained a foothold. 

As soon as the goods are removed from cold storage rooms 
the frost on cooling pipes should be removed and taken out of the 
room. If the fan system of air circulation is employed, with the 
coils all located in a coil room or bunker, this is a comparatively 
easy matter to attend to. Where the pipes are directly in the 
room, the resulting slop will necessarily cause the floor and walls 
to become damp to a greater or less extent. Moisture on floors 
of cold storage rooms should be taken up by throwing down dry 
sawdust or air slaked lime. It should be removed at once and 
not allowed to soak into the floor lining or insulation. A few 
barrels of dry sawdust should be on hand at all times for the 
purpose of soaking up melting frost or possible leakage from 
any cause. With the coil room and fan system the floor of 
coil room is usually water tight and properly connected with out- 
let to drain system so that damage to insulation cannot occur 
in this way. 

After removing the frost from refrigerating pipes, meas- 
ures should be taken to keep the rooms dry and pure. This may 
be done by exposing a quantity of quicklime in the room. It 
may be placed on the floor, but should not be placed on any wet 
spots unless it has already been air slaked and is in powdered 
form. It might under some circumstances cause the starting of 
a fire from the heat of slaking. Chloride of calcium placed on 
trays or pans or supported on a screen shelf above a water-tight 
pan, as illustrated in the chapter on "Uses of Chloride of Cal- 
cium/' may be used to good advantage. Where the coil room and 
fan system are in use, chloride of calcium may be supported in 
the coil room as in the author's patented chloride of calcium 
process, or in any other suitable way, and by operating the fan 
a short time at intervals the room may be kept in a pure and dry 
state. During cool or cold weather it is a good plan to allow 
the air to blow through the rooms when it is dry outside and 
about the same or a little lower than the temperature of the room. 
W^hat is still better is the cold weather ventilating system, which 
is described in the chapter on *'\'cntilation.'' With this sys- 


tern fresh air may be taken from outside the cold storage building 
and forced into the room in large quantities and the foul air from 
the room is allowed to escape through a suitable vent. The in- 
coming air may be forced directly into the room without heating, 
or it may be heated to any required temperature by passing it 
over a steam coil or jacketed heater. 

A few words in regard to the proper preparation of new 
cold storage buildings for the receiving of goods may not be out 
of place here. In the finishing up of a cold storage building it 
very often occurs that the work has to be rushed and enough 
time is not allowed for the proper whitewashing of the wood 
lining or interior surfaces of the room. This situation demands 
care and rapid work and advantage must be taken of all 
opportunities for whitewashing the rooms as fast as they are 
ready or as soon as a portion of their surfaces is ready. Keep 
men at work whitewashing following up the carpenters. By 
keeping the doors open and using the ventilating system intelli- 
gently, if one is installed, some of the rooms may be ready to 
receive goods as soon as the refrigerating equipment is ready to 
supply refrigeration. If no other means of properly drying are 
at hand, use chloride of calcium as illustrated in chapter referred 
to. In whitewashing cold storage rooms for the first time, it is 
advisable to apply first a thin coat of whitewash so that it may 
penetrate the wood as much as possible. It will also make a 
better ground for the second coat. The second coat may be 
somewhat thicker and should not be applied until the first coat 
is thoroughly dry. 


The proper drying out of whitewash in cold storage rooms 
is a difficult matter, owing to the inclosed nature of the rooms, 
which are usually provided with but one opening, also to the 
low^ outside and inside temperatures which usually prevail at 
the time of whitewashing. The cold weather ventilating system, 
already referred to, is of great assistance at such a time. By 
applying heat to the rooms and allowing the cold, moist air to 
escape as the dry, warm air is forced in, the whitewash may be 
dried very thoroughly. It is customary in some plants, especially 
in the larger cities where some of the rooms are in service during 


the greater part or all of the year, to dry out the rooms by placing 
a "salamander," or sheet iron heater for burning coke or char- 
coal, in the room. This is not a very scientific nor practical 
method, as the moisture driven out of the room in which the 
salamander is placed is conveyed to other rooms of the house or 
into the corridor to some extent ; besides this, the salamander 
will dry out only a portion of the room at a time. The gas gen- 
erated is also very objectionable and even dangerous to persons 
working in the room. In using a salamander it is best to light 
the fire and allow it to get well started before taking into the 
storage room. In this way a large part of the gas is avoided. 
For the most nearly perfect job of w^hitewashing from five to 
eight days are required to dry thoroughly. If the whitewash 
dries rapidly, as it may when a salamander is used, it will flake 
off and not be permanent. On the other hand, if it does not dry 
within a reasonable length of time, the water in same will soak 
into the wood and, in finally drying, the whitewash will have a 
dark or mottled appearance. Rapid drying, therefore, should be 
avoided as well as slow drying. 

The importance of attending to the matter of whitewashing 
in new houses which are rushed to completion can not be too 
strongly dwelt upon. The author has repeatedly come in contact 
with this situation and much time and eflfort have been expended 
by him in trying to get whitewashing properly done and at the 
right time. Those new to the business do not appreciate the 
importance of whitewashing and the necessity of looking after it 
carefully. Very bad results have in numerous cases followed 
the careless daubing on of whitewash, and allowing it to dry at 
its own pleasure. In some cases butter has been very strongly 
flavored in a way which could not be accounted for ; again, eggs 
are damaged, and other goods to a greater or less extent, de- 
pending on their sensitiveness. If whitewash is plastered on the 
walls too thick and does not dry, the water contained therein 
penetrates the wood and may cause a fermentation, w^hich leads 
to a peculiar bitter or strong smell in the room, which in turn 
will flavor the goods. If the case is an aggravated or serious 
one, mold will develop, and the serious nature of this trouble 
is too well understood to need description. Whitewashing should 
be done in the winter or during weather when the air is about 


as cold or colder outside than inside the storage rooms. It is 
then much easier to get the rooms dry. Bad effects have followed 
whitewashing during warm weather, because it is so difficult to 
get the rooms to dry properly. 

It is a popular idea, and yet entirely wrong, tnat most any- 
body can prepare and apply whitewash. Of those who think 
they know how to whitewash, probably not one in ten knows how 
to slake the lime. This should be done in one of two ways, either 
of which is good. The author recommends the following: Take 
one-half bushel of lime and place it in a half -barrel (an oil bar- 
rel or vinegar barrel which has been cut down makes a good 
utensil for this purpose) ; pour on a small quantity of boiling 
water, barely sufficient to cover the lumps of lime ; keep the lime 
well stirred clear to the bottom (a piece of one-inch gas pipe 
about five or six feet long is the best stirring stick). In case the 
lime is very quick, it should require two persons to slake the lime, 
one to pour on the water as needed and one to stir. The stirring 
should be kept up continuously from the time the lime begins to 
slake until it is reduced to a paste, and water should be added as 
fast as the lime slakes, so as to keep it at a rather thin, pasty con- 
sistency. It is very common to see lime placed in a barrel and 
water turned on and the lime allowed to slake itself. The result 
is that the whitewash is full of small pieces or lumps which are 
not slaked, but are burned as the result of water riot coming in 
contact with the lime at the right time. It is not absolutely neces- 
sary that boiling water should be used, but unless the lime is 
quite quick, it facilitates the operation and results in more thor- 
ough slaking. Another method which may be employed is to 
place the lump lime on a cement floor and sprinkle water on 
slowly as the lime slakes. If this is handled carefully and at- 
tended to the result will be a finely-powdered slaked lime, which 
may be mixed with water to a proper consistency. The author 
does not recommend this method as compared to the one first 
described, as it is slower and there is much more danger of burn- 
ing the lime and causing the whitewash to be lumpy. 

A large number of those who replied to the circular letter 
of inquiry are using the Government formula for making white- 
wash, but one of the ingredients of this formula is rice boiled 
to a thin paste, which makes it seem difficult to the average per- 


son, and, further than this, the author does not believe in using 
any organic substance in preparing whitewash. For those who 
prefer the Government formula it is here given : 

Slake half a bushel of quick lime with boiling water, keep it covered 
during the process. Strain it and add a peck of salt dissolved in warm 
water, three pounds of ground rice put into hoiling water and boiled to 
a thin paste, half a pound of powdered Spanish whiting, a pound of clean 
glue, dissolved in warm water: mix these well together and let the mix- 
ture stand for several days. Keep the wash thus prepared in a kettle or 
portable furnace and put it on as hot as possible with either painters' or 
whitewash brushes. 

It is better to use the mineral substances, and the following 
has given good satisfaction under most circumstances: One- 
half bushel of lime, slaked with hot water, as previously de- 
scribed. When the lime is thoroughly slaked, add one peck of 
salt. It will be neces.sary to add more water as the salt is added, 
in order to keep the whitewash at the proper consistency : or 
the salt may be dissolved separately in as small an amount of hot 
water as will absorb it readily. The proper consistency for 
whitewash is a thin paste and it may be teirpcred as it is used. 
To each twelve-quart pail of whitewash, composed of lime and 
salt as above, add a good, fair handful of Portland cement and 
about a teaspoonful of ultramarine blue. The cement and blue 
should be added only as the wash is being used and should be 
thoroughly stjrred into the whitewash; otherwise, when applied, 
it will be streaked. Cement is used for the purpose of giving 
the whitewash a better setting property so as to make it ad- 
here better to the surface to which it is applied. The ultramarine 
blue is u.sed simply to counteract the brownish color of the Port- 
land cement. If white hydraulic cement is obtainable, it is better 
to use than Portland cement, and in this case the ultramarine 
blue may be dispensed with. It is, however, best to use a small 
amount, say half a teas])oonful to the pail, as a whiter surface 
results. The wash should be strained through a fine wire-cloth 
strainer before using, to remove the lumps if there are any 


The advisability of using whitewashing machines or spray- 
ing pumps in cold storage work has been an open question for 
some time. Of the replies received, about one-half recommend 


the use of the machine. Some say the machine will do the best 
work, but this is not the author's experience. There are some 
situations where the machine is a decided advantage; for in- 
stance, on overhead work, between open joists, or any surface 
which is difficult to get at with a brush. It is hardly possible to 
get as smooth and even a job with the machine as it is by hand, 

j and, besides, a machine will necessarily put a good deal more 

whitewash on a given amount of surface than is put on with 

j brushes. This is objectionable, for the reason that a heavy bed 

of whitewash on drying will flake off much more quickly. In 
some cases, those who use a machine go over it with a brush while 
still green in order to make it smooth and even. Another ob- 

I jection to a machine is that it will cause a mist in the air and the 

' whitewash will spatter over any object in the room. A room 

must be entirely empty in order to use a machine. It should not, 

! of course, be inferred that it would be practicable to whitewash 

a room while goods are stored in same, but it is necessary to 
clean a room out of ci*cry thing that is liable to be injured by the 
whitewash in order to use a machine. The spray is also very 
uncomfortable for the operator. A moderately thin coat of white- 
wash on old work is as good for purifying purposes as a thick 
one ; and for this reason handwork is to be preferred to machine, 
as much less material may be applied. The more whitewash 
put on the more water to be gotten rid of in some way, and if 
the water is not removed promptly very bad effects may result, 
as already noted in discussing the drying out of cold storage 
rooms after whitewashing. 

The author's impression is strongly in favor of hand-work, 
but it is not a desirable job for the man who has to do the work. 
It is probable for this reason that the machines are gaining head- 
way. They have also been perfected to quite an extent during 
the past few years. There are a good many different makes of 
first-class machines on the market. The same machine that fruit 
growers use for spraying trees is available for whitewashing 
and the same machine is commonly sold for both purposes. 

Good work in whitewashing should look well, be perfectly 
white or nearly so, should be hard and not liable to flake off or 
dust off onto the hands or clothing, and should have complete 
disinfecting and germ-killing properties. The slaking of the lime 


is the most important part of the operation and the success of 
same depends upon the care and attention given. Too much care 
can not be given to this detail, and cold storage men should see 
to it that whoever has this in charge looks after same conscien- 
tiously. Lime that is burned or drowned in slaking is not firm 
in texture when applied and is not as disinfecting nor fireproof 
as it should be. 


There are many good cold-water paints on the market under 
various names which are advisable in some places for which 
whitewash is not well adapted, and many use them for all interior 
surfaces. For butcher's boxes or retail coolers especially they 
are preferred to whitewash, for the reason that they will not flake 
off readily. It is also good for doors and corridors of cold storage 
houses. Most of these cold-water paints are composed of secret 
ingredients, and some contain organic substances like glue, which 
makes their use inadvisable for cold storage purposes, except in 
special situations. Shellac is also largely in use for cold storage 
rooms, but it has no disinfecting or cleansing properties like 
whitewash. It makes a beautiful finish where the lumber in use 
has a good natural grain. Shellac has the advantage of being 
waterproof, and therefore walls may be easily washed at any 
time. It is, perhaps, unnecessary to state Ihat any oil paint, or 
any other preparation with strong odor, has no place about the 
cold storage rooms or the corridors or other approaches thereto. 

In connection with the whitewashing of rooms and their 
cafe during periods of idleness, it has seemed proper to take up 
the cleaning and painting of the pipes or refrigerating surfaces 
which cool the room. The answers to the questions covering this 
subject indicate that it is not customary among cold storage 
men to paint their pipes after they are once installed, and this is 
strictly in line with the author's ideas and experience on the 

There are two good reasons why the painting of pipes is 
not advisable after they are once put in place in the cold storage 
plant; first, it does not pay; second, it is dangerous. It does 
not pay, because after the pipes are once put in place a good job 
of painting cannot be done unless the coils are entirely removed 



from their supports so that they can be painted on both sides. 
The labor involved in removing the refrigerant, taking down 
the pipes, cleaning them and applying the paint is considerable, 
and the cost of the paint is no insignificant item. A good paint 
put on the pipes before they are set up in the cold storage house 
will protect them fairly for a period of from two to three years, 
more or less. Before the coils are set in place it is comparatively 
easy to paint them and it is recommended that coils should be 
painted when new. It is especially desirable to paint them at this 
time, as the pipes are clean and free from scale or rust. After 
the pipes become rusty from service, it is almost impossible to 
get them sufficiently clean so that the paint will adhere properly. 
Considering the low price of pipe and its comparatively long life 
when used w^ith ammonia or chloride of calcium brine, it does not 
seem to warrant the expense. It is dangerous to paint pipes in 
a cold storage room for the reason that no paint known to the 
author is non-odorous or anywhere near it. The pipes should, 
therefore, be removed from the rooms for painting and allowed 
to dry and deodorize before they are returned to the cold storage 
room. This, however, is rather impracticable and it adds to the 

For painting pipes, various preparations have been used w-ith 
more or less success. There are a number of patented and pro- 
prietary preparations on the market which are good and are 
sold at a reasonable price. Red lead and boiled oil is also an old 
stand-by for this purpose, but it is much more expensive than 
some of the preparations alx)ve mentioned. Boiled linseed oil 
without any pigment as a coating for refrigerating surfaces will 
give good protection from rust for a limited time, but the com- 
mercially prepared products will be found superior though some- 
what more expensive. 




The information following is largely a compilation of the 
opinions of farmers, merchants and shippers in all parts of the 
country, which wxTe received in reply to a circular letter sent out 
by the United States Weather Bureau. The principal kinds of 
goods which are considered perishable, and for which protection 
from excessive heat or cold is necessary are: All fruits and 
vegetables, milk, dairy products, fresh meats, poultry, game, fish, 
oysters, clams, canned fruits and vegetables, and most bottled 
goods. In the transportation of perishable freight there are 
three primal objects to be attained: 

I. — The protection of the shipment from frost or excessive 

2. — The protection of the same from excessive heat. 

3. — The circulation of air through the car, so as to carry off 
the gases generated by some classes of this freight. 

[It is not plain how a circulation of air will carry off gases 
from goods. Probably what is meant is to call attention to the 
importance of air circulation to purify the air and maintain 
uniform temperature. See chapter on "Air Circulation."] 

The degree of cold to which perishable goods may be sub- 
jected without injury varies greatly with different commodities, 
and depends somewhat on the time the shipment will be on the 
road, its condition when shipped, wdiether it is kept continually 
in motion, and also on whether it is unloaded immediately upon 
arrival at its destination, or allowed to stand some time. The 
direction of shipment, whether toward a cold area or away from 
it, should also be considered. 

♦Abstracted from Farmers" Bulletin No. 125, United States Department of Agricult- 



Precautions taken in shipping to protect from cold are pack- 
ing in paper, straw or sawdust, boxing, barreling with paper 
lining, shipping in paper lined cars, refrigerator cars, and cars 
heated by steam, stoves and salamanders. 

Shippers and agents concur in the statement that danger in 
transportation by freezing can be practically eliminated by the 
shipment of produce by modern methods; the lined car suffices 
in spring and autumn, and usually during winter, while in ex- 
tremely cold weather specially built cars are used. 

In ordinary freight cars perishable goods can be shipped 
with safety with the outside temperature at 20° F., and in refrig- 
erator cars at 10°. In the latter these goods may be safely 
shipped with an outside temperature of from zero to 10° below, 
if the car is first heated, and at the end of the journey the goods 
are humediately taken into a warm place without being carted 
any great distance. 

[Any statement cannot be as positive as this and be accurate 
when applied to so varying a subject as shipping of perishable 
goods. The protection of food products in shipment during 
extreme cold weather depends on several things with a great 
variation of conditions. Fully as much depends on the tempera- 
ture of the goods themselves as on the temperature of the car 
and the use of insulating substances for packing the goods or 
the use of an insulated car. Take as an example the shipping 
of eggs : If loaded into a good refrigerator car at a temperature 
of 30° F. (as when loading from ihe cold storage room) no 
amount of protection or the use of an extra well insulated car 
will prevent freezing if on the road for several days with an 
outside temperature below zero. On the other hand, if started 
at a temperature of from 45° to 50° F. a moderate protection will 
suffice, and the regular refrigerator car will take them through 

To protect goods shipped in an ordinary car, the sides of 
the car should be protected by heavy paper tacked to the wall, 
and by the addition of an inner board wall, a few inches distant 
from the outer one. A car thus equipped and packed with prod- 
uce, surrounded by straw, will retain sufficient heat to prevent 
injury for twenty-four hours, the average air temperature inside 


llie car being at least twelve degrees higher than the outside 
air. Cars are sometimes warmed by steam from the locomotive 
when in motion, and by stoves when steam is not available. Cars, 
after being loaded, are carefully inspected as to temperature 
within; their destination is considered; and, if the weather is 
exceedingly cold, or is liable to be, the car is often accompanied 
by an attendant; otherwise it is inspected from time to time on 
the road. Lined cars — that is, cars lined with tongued and 
grooved boards on the sides and ends — ^are considered the best 
for shipping potatoes, as they can be heated by an ordinary stove 
and will stand a temperature outside of 20° below zero, when 
a man is in charge to keep up the fires. 

[The most approved arrangement in a potato shipping car 
is a false floor and a partial false ceiling to allow of a circulation 
of air. The stove is placed in the center and the warm air 
ascends to the ceiling where it passes along to the ends of the 
car, descending and returning under the false floor to the stove 
in center of car.] 


The better class of refrigerator cars will carry all perishable 
goods safely through temperature as low as 20° below zero, pro- 
vided they are not subjected to such temperature longer than 
three or four days at a time ; but with the ordinary refrigerator 
cars a temperature of zero is considered dangerous, especially if 
the goods they contain be of the most perishable kind. 

In winter time refrigerator cars are used without ice in for- 
warding goods from the Pacific coast; in passing through cold 
belts or stretches of country the hatches are closed, and the cars 
being lined and with padded doors, the shipment is protected 
against the outside temperature; in passing through warmer 
climates the ventilators are opened in order to prevent the perish- 
able goods from heating and decaying. 

It is stated, however, that for the shipment of fruit the ordi- 
nary refrigerator car is not entirely satisfactory, and that there 
is a strong demand for a better refrigerator car than can now 
be obtained. [The author knows this to be a fact. The re- 
frigerator cars now in use have been designed for the most part 
by men of moderate scientific or mechanical knowledge, and 


present great opportunity for improvement. Owing to the 
nature of the companies controlling the refrigerator car business, 
the practical engineer has little opportunity of introducing im- 
proved methods in the construction of refrigerator cars.] A 
car is wanted that will carry oranges, bananas, etc., without dan- 
ger of chill through the coldest climates of the country, as the 
delays in housing are injurious to the keeping qualities of the 
fruit, and the dealer is also kept out of the use of his goods. 

The following is a description of a nuich used patent refrig- 
erator car: 

**The car is double lined and has at each end of the interior 
four galvanized iron cylinders, reaching from the floor to near 
the top. Ice is broken to pieces about the size of the fist, and 
the cylinders filled with this ice and salt, the whole being tamped 
down hard. It is claimed that cars iced in this manner do not 
need re-icing in crossing the continent, as other styles of cars do. 
The car is iced in winter in the same manner as in summer, as 
such icing prevents freezing." 

[An absurd statement. Icing and salting will not prevent 
freezing, and there is no use in icing during cold weather. If 
tanks could be filled with water, freezing of goods in the car 
would be in some cases prevented.] 

The car that has the most floor space and will hold the 
greatest quantity of ice is preferred by most shippers. 

^listakes are often made in building fires in round-houses 
where cars of produce are stored, unnecessarily heating it, a 
uniform temperature, just above the danger point, being the most 


In 1895 an experiment for testing the advantages of dif- 
ferent modes of ventilation during the shipment of fruit was 
made under the direction of the Riverside Fruit Exchange, of 
Riverside, Cal. Five cars loaded with oranges were shipped a 
distance requiring a seven days* run. Four refrigerator cars 
and one ventilated or fruit car were used. Two of the refrig- 
erator cars had the ventilators closed from 4 a. m. till 8 p. m. 
each day, and open the remainder of the time. The other two and 
tlie fruit car had ventilators open during the entire trip. Ob- 


servations were made of the outside and inside temperatures at 
4 and 9 a. m. and 3 and 8 p. m. In the first two cars the inside 
temperature ranged from 46° and 42° F. minimum to 56° and 
58° F. maximum, respectively ; in the second two, from 48° and 
44° F. minimum, to 58° and 62° F. maximum, respectively ; and 
in the fruit car from 42° minimum to 68° maximum. The out- 
side temperatures ranged from eight degrees lower to nineteen 
degrees higher than the inside. It was found that the tempera- 
ture varied less in the refrigerator cars than in the fruit cars, 
owing to the fact that they were better insulated. It was also 
found that the fruit in the cars which had the ventilators closed 
during the day arrived in much better condition than that in the 
cars W'hich had the ventilators open. 


The relation between the outside air temperature and the 
temperature within the car varies largely, depending on the kind 
of car, whether an ordinary freight or refrigerator car, whether 
lined or not, whether standing still or in motion; and also on the 
weather, whether windy or calm, warm or cold. In an ordinary 
freight car the difference ranges from two to fifteen degrees, and 
in a refrigerator car from fifteen to thirty degrees. If the latter 
be provided with heating apparatus, the temperature in winter 
can be kept at any required degree. 

From six observations taken at intervals of ten minutes, it 
was found that on a warm day, when the mean of the six read- 
ings outside was 68°, it was 66° F. on the inside of an ordinary 
freight car, and 63° F. inside of an uniced refrigerator car. On 
a cold day the mean of six observations was 38° F. outside and 
35° F. inside of an ordinary car. and 36° F. inside of a refrig- 
erator car ; the cars were stationary. 

Freight from the Pacific coast to the Mississippi valley, or 
to the Atlantic coast, has to pass through several varieties of 
climate at any time of the year, so that at one time the tempera- 
ture inside the car will be materially above the outside tempera- 
ture, W'hile perhaps a few hours later it will be below. 

Products sent loose in a car are packed in straw on all sides, 
particular attention being paid to the packing around doors, and 
to see that the car is full. Manure is largely used to protect 


perishable goods, the bottom of the car being thickly covered 
with it, and in some cases it is put on top of the goods. 

[No sane man would use manure in a car with perishable 
goods unless they were in some sealed package like cans or 
bottles. In any case straw, or better still, mill shavings are 
better than manure for any purpose of this kind.] 

The temperature of the produce when put into the car is 
quite a factor to be observed. If it has been exposed to a low 
temperature for a considerable time before, it is in a poor condi- 
tion to withstand cold, and the length of time so exposed should 
be taken into account. It is also claimed that a carload of 
produce, like potatoes, will stand a lower temperature when the 
car is in motion than when at rest. 

[One of the old popular ideas without material foundation. 
Men and animals will withstand low temperature best when in 
motion, but this does not apply to perishable goods.] 

Goods at a temperature of 50° to 60° F., packed in a refrig- 
erator car, closed, have been exposed to temperatures 10° to 20° 
below zero for four and five days without injury. 


In shipping fresh meats the almost universal practice is to 
ship in refrigerator cars where the temperature can be main- 
tained at any desired degree, a temperature from 36° to 40° F. 
being considered the best. 

Beef. — Fresh beef for shipping should be chilled to a tem- 
perature of 36° F., although under favorable conditions it will 
arrive in a good state if chilled to only 40° F. The cars should 
be at the same temperature as the chill room, and it is considered 
very important to have an even temperature from the time the 
beef is taken from the chill room until its arrival at its des- 

In shipping long distances in summer, it, is necessary to 
re-ice the cars, the frequency depending on the prevailing tem- 
perature, so that no fixed rule can be given. In winter the tem- 
perature is kept up to 36° F. by means of stoves or oil lamps. 

If refrigerator cars are not used, the meat should be wrapped 
in burlaps, and the carcasses hung so as not to touch each other. 
With an outside air temperature of 50° F., or below, in dry 


weather, meat that has been thoroughly cooled will keep a week 
if shipped in an ordinary box car. 

Pork. — Pork is injured more quickly by high temperature 
than other meats, and greater care should be taken with it in 
storing and shipping. Sudden changes in temperature of from 
io° to 20° F. are very injurious to fresh meats, and should be 
provided against when possible. 

Poultry. — Poultry, if shipped at a temperature of so"* F. 
or higher, should be packed in ice and burlaps ; if under 50° F., 
in dry weather, no extra precautions are needed. In shipping 
live poultry the coops are frequently overcrowded, resulting in 
the death or great deterioration of many of the fowls. 


Milk. — Milk for shipping requires great care to prevent 
souring; it should be reduced after drawing to a temperature of 
40° F., which extracts the animal heat. It should never be 
frozen, as it becomes watery and inferior in quality when 
thawed out. 

Eggs. — Eggs are packed in crates with separate pasteboard 
divisions, with a layer of excelsior top and bottom. Pickled 
eggs are injured by cold sooner than fresh ones. 

A prominent wholesale dealer in butter, eggs, and cheese at 
Chicago, says: 

Eggs in storage and transportation cannot stand a lower temperature 
than 28** F. ; if packed well in cases and loaded in a refrigerator car they 
usually come through in good condition at from 5° to 10** below^ zero, and 
at 10° above zero in common cars, if not exposed more than forty-eight 

Butter and Cheese. — A wholesale butter and cheese firm of 
Chicago writes as follows: 

Butter is probably unaffected by extreme cold. We have never ex- 
perienced any damage by butter being too cold ; in fact, in carrying it in 
cold storage, it is carried at from zero to 10° above ; but extremely warm 
weather is very injurious and damages the article to a considerable extent. 
To preserve butter it should be kept as cold as possible, as we state above, 
all the way from 32° above down to zero. It all depends upon what the 
facilities are for carrying the same. Of course, when we place it in 
cold storage the temperature we would require would be zero to 10* above, 
and, of course, that temperature w-e cannot have in handling it when we 
come to sell it out in our store, but we take great care not to take out 
of storage any more than can be readily sold. In regard to cheese, extreme 
cold and extreme heat are both injurious to same. For instance, extreme 


heat will cause cheese to swell and ferment [Not if the cheese is well 
made. Extreme heat injures cheese by starting the butter fat, which 
causes the cheese to become dry and crumbly.], while extreme cold will 
freeze it; the curd becomes dry and like sawdust, and it will never 
again be firm and stick together, but will crumble. It takes quite a 
temperature to freeze cheese, say io° above for one or two days out on 
the road would freeze it. It is very slow in freezing and very slow in 
thawing out. A skim-milk cheese will freeze quicker than a full cream 


Fish. — Fish are shipped by express and also by freight. 
When shipped by express they are packed in barrels with ice. 
When shipped by freight they are packed in casks holding 600 
pounds each, or in boxes on wheels, holding about 1,000 pounds 
each. When shipped in carload lots they are packed in bins 
built in the car and thoroughly iced. The amount of ice supplied 
should equal one-half the weight of the fish. Fish keep best 
when the temperature of the box in which they are stored is 
about that of melting ice. Under favorable conditions fish 
remain sound and marketable for thirty days after being caught 
and packed in ice. The entrails of fish should be removed before 
shipping, as they are the parts that most readily decay, and taint 
the flesh of the fish. This is especially necessary in shippinc^ 
long distances. 

Oysters. — Shucked oysters, shipped in their own liquor in 
tight barrels, will not spoil if frozen while in transit. Thick or 
fat clams or oysters will not freeze as readily as lean ones, as 
the latter contain much more water. Oysters will not freeze as 
readily as clams. It is safer when oysters or clams in the shell 
are frozen to thaw them out gradually in the original package 
in a cool place. 

In freezing weather oysters and clams, in the shell, are 
shipped in tight barrels lined with paper. 


It is imix)rtant to note that in shipping fruits, etc., many of 
the precautions taken in packing to keep out the cold will also 
keep in the heat, and there is really more danger in some in- 
stances from heating by process of decomposition than from cold. 
All fresh fritit tends to generate heat by this process. A car load 


of fresh fruit approaching ripeness, closed up tight in an uniced 
refrigerator car, with a temperature above 50° F., will in twenty- 
four hours generate heat enough to injure it, and in two or three 
days to as thoroughly cook it as if it had been subjected to steam 
heat. [This heating action is of small moment if the fruit is 
cooled before placing in the car to a temperature of 40° F. or 
lower.] Suitable refrigerator transportation must, therefore, 
provide for the heat generated within, as well as the outside heat. 
The perfection of refrigeration for fruit is not necessarily a low, 
but a uniform teniperature ; a temperature from 40° to 50° F. 
will keep fruit for twenty or thirty days, if carefully handled. 
Strawberries have been transported from Florida to Chicago, 
transferred to cold storage rooms, and remained in perfect con- 
dition for four weeks after being picked. [An uncommon or 
trial shipment. These results cannot be duplicated on a commer- 
cial scale.] 

Fruit intended for immediate loading in cars should be 
gathered in the coolest hours of the day, and that which has been 
subjected to a high temperature before being shipped should 
be cooled immediately after being loaded. Ordinary refrigera- 
tion will not cool a load of hot fruit within twenty-four hours, 
and during that time it will deteriorate in quahty very much. 
It should be cooled in four or five hours in order to prevent 
fermentation. It is stated that the more intelligent of the large 
shippers of fruit in the south have about concluded that it is 
impracticable with any car now in use to load fruit, especially 
peaches and cantaloupes, direct from the orchard into the car 
with assurance of safety. In deference to this opinion one south- 
ern railroad has announced its intention of establishing at the 
largest shipping points along its lines, cooling rooms for the 
purpose of putting the fruit in satisfactory condition for trans- 
portation before being loaded. 

Shipments of tropical fruits in ordinary freight cars cannot 
be safely made when the temperature is below 30° F., except in 
cases where the distance is so short as not to expose them for a 
longer period than twelve hours, and even then they must be 
carefully packed in straw or hay. The hardier Northern fruits 
and vegetables can be safely shipped in a temperature of about 
25° F., but the same protective measures must be employed as 


in the case of tropical fruits when lower temperatures prevail. 
Long exposure to temperature of 20° F. is considered dangerous 
to their safety. Foods preserved in cans or glass should not be 
shipped any distance when the temperature is below the freez- 
ing point. 

Oranges and Lemotis. — Oranges shipped from Florida to 
points as far north as Minnesota are started in ventilator cars, 
which are changed at Nashville to air-tight refrigerator cars, 
the ventilators of which are kept open, provided the temperature 
remains above 32° F., until arrival at St. Louis, from which point 
the ventilators are closed and the cars made air tight. Lemons 
and oranges are packed in crates. Each layer of crates in the car 
is covered by and rests upon straw, usually bulkheaded back 
from the door and car full. Oranges loaded in ventilated or 
common cars should be transferred to refrigerator cars when the 
temperature reaches 10° above zero; in transit, with a falling 
temperature, the ventilators should be closed when the ther- 
mometer reaches 20° F., and with a rising temperature the ven- 
tilators should be opened when it reaches 28° F. For lemons, the 
minimum is 35° F. for opening and closing the ventilators, and 
for bananas 45° F. for opening or closing. Some shippers say 
that ventilators on cars containing bananas, lemons and other 
delicate fruits should be closed at a temperature of 40° F. 

Bananas. — In shipping carloads of bananas a man is usually 
sent in charge to open and close the ventilators. Bananas should 
be put in a paper bag and a heavy canvas bag, and then covered 
with salt hay, unless put in automatic heaters, when the fruit is 
packed only in salt hay. Bananas are particularly susceptible to 
injury by cold, and require great care. If exposed to tempera- 
tures as low as 45° F. they almost invariably chill, turn black 
and fail to ripen. Cars containing them are sometimes, in ex- 
treme cold weather, protected by throwing a stream of water on 
them, which, freezing, forms a complete coating of ice. The 
method adopted by some firms, of shipping this fruit in winter, 
is to heat refrigerator cars to about 90° F. by oil stoves, remove 
the stoves and load the fruit quickly, put the stoves back and heat 
up to 85° or 90° F., then remove the stoves again, close the car 
tight, and start it on its way. Bananas shipped in this manner 


are held to be safe for forty-eight to sixty hours, even though 
the temperature goes to zero. 

Quinces, apples, and pears are packed in barrels, each layer 
of barrels covered with and resting on straw. [Straw is really 
only necessary on the bottom, top, sides and ends of car; no 
useful result is obtained by packing straw between barrels.] 


Potatoes are packed in straw, bulkheaded back, the center 
of the car left empty, and the car filled as high as the double 
lining. When the temperature is 12° F. or more below freezing, 
the rule is to line the barrels with thick paper, and at extremely 
low temperatures, as a matter of extra precaution, the barrels arQ 
covered over the outside with the same kind of paper. 

In shipping early vegetables to a northern market from the 
South, for distances requiring more than forty-eight hours to 
cover, openwork baskets, slatted boxes, or barrels with openings 
cut in them should be used to allow a circulation of air. 

As a rule, truckers will not haul vegetables to the cars for 
shipment when the temperature reaches 20° F. or lower, and in 
no case when it is near 32° F. if raining or snowing. 

[A point in connection with the transportation of perishable 
goods not touched on is the importance of not overloading refrig- 
erator cars with fruit or other goods of like nature. The warm 
air from goods will accumulate in the upper part of the car, and 
no refrigerator car now in service so far as known to the author 
has a circulation of air sufficiently perfect to give even approxi- 
mately uniform temperatures. It is generally necessary to leave 
at least a foot or eighteen inches space at top and space between 
packages for air circulation. California fruit shippers fully ap- 
preciate this and always tack strips of wood between packages, 
which holds the packages in place and allows of good air cir- 


In connection with the shipment of food products liable 
to injury by heat or cold, much benefit may be derived from an 
intelligent use of the information contained in the daily weather 
reports and forecasts published by the Weather Bureau, which 


show the temperature conditions prevailing over the whole coun- 
try at the time of the observations, the highest and lowest tem- 
peratures that have occurred during the past twenty-four hours, 
and the probable conditions that will prevail during the next 
twenty-four or thirty-six hours. These reports and forecasts are 
received at nearly every Weather Bureau office, of which there is 
one or more in nearly every State and Territory, and published 
on maps and bulletins, which are posted in conspicuous places 
in the city where the office is located, and mailed to surrounding 
towns. The reports, or a synopsis of them, are also generally 
published in the daily papers. 

l^uller information than is obtainable from either of these 
sources may be had at the Weather Bureau office itself, from the 
observer in charge, or, where none of these means is available, 
arrangements may be made with the observer to supply special 
iti formation by mail, telephone, or telegraph. In the large cities 
(^f the country, dealers in perishable goods are guided in their 
transactions very largely by the information thus obtained. The 
temperature of the region to which shipments are to be made is 
carefully watched, and the shipments expedited or delayed, ac- 
cording as the conditions are favorable or unfavorable. Ship- 
ments on the road are protected from injury by telegraphic in- 
structions as to the necessary precautions to be taken. As ship- 
ments in ordinary box cars, or as freight, are less expensive 
than in refrigerator cars or by express, advantage is taken of a 
favorable spell of weather to use the former methods. 

Infomiaiion as to the altitude of the regions traversed by 
the shipping routes, such as may be obtained from the contour 
maps published by the I'niied States Geological Sur\ey. the lo- 
cation and capacity of the roundhouses along the routes, and the 
IXMUIS on the railroails where transp. rtation is liable to blockage 
l\v snowdrifts, in connection with ibat given by the daily weather 
maps, will prove of value to the ship|K"r in the supervision of his 

In sbipiMig early vegetables Xonh from Stnilhem f>-*ris 
the woaiher rej^^^ns are utilized to deiemiine whether to use 
water or rai-r.^nd transportation, the foniier being the cheaper. 
IVaiors in certai:^. kin*!> ot pnxluoe, by careful attention to the 
iKir.y weather rep rts and the weekly crop bi:-!ttins. keep the-r.- 


selves informed as to the sections where conditions most favorable 
for large crops have prevailed, and are thus enabled to judge of 
the probable supply and to know where to purchase to advantage. 

As illustrations of the manner in which advantageous use 
may be made of the weather reports, suppose a merchant in Ohio 
has an order in January for a load of apples or potatoes to be 
shipped to St. Paul; when his shipment is ready he may ascer- 
tain by personal inquiry at the Weather Bureau office, or by a 
study of the published reports and forecasts, the probable tem- 
perature conditions between Ohio and Minnesota for the period 
that the shipment is likely to be on the road, and regulate the 
same accordingly. If neither of these means of information is 
accessible to him, he may telegraph the observer at the nearest 
Weather Bureau office, Cincinnati, Columbus, Cleveland, San- 
dusky, or Toledo, as the case may be, requesting the information, 
or he may arrange beforehand with the observer to be informed 
by telegraph when the conditions are favorable for making the 
shij)ment, the cost of all telegrams, of course, to be borne by him- 
self. While the consignment is on the road he should still keep 
himself informed as to the temperature conditions of the region 
through which it passes, and if injuriously low temperatures 
are likely to occur, may telegraph to have it housed or otherwise 
protected until the conditions are again favorable. By the use of 
similar means, a packer having a large number of hogs to 
slaughter may ascertain in advance when temperatures favorable 
for that purpose are likely to prevail in his locality; or a South- 
ern merchant having a consignn:ent of tropical fruit on the road 
lo the North may insure its protection from injuriously high or 
low temperatures by telegraphic instructions as to the opening 
or closing of ventilators, or the use of ice or artificial heat. 

During the season when cold waves are liable to occur, a 
careful watch of the reports and forecasts will often enable 
dealers and others to protect from injury large quantities of prod- 
uce in storage. Instances are numerous where the use of such 
information has resulted in large pecuniary benefit. 

During the severe cold wave of January i to 5, 1896. which 
overspread nearly the entire United States east of the Rocky 
Mountains, over three and one-half million dollars' worth of 
property was saved from destruction by the warnings of the 



Weather Bureau, which were sent out in advance of the wave. 


In the following table are given the highest and lowest tem- 
peratures which perishable goods of various kinds will stand 
without injury, whether packed in ordinary packages, stored in 
freight cars or placed in regular refrigerator cars. [The tem- 
peratures given seem to the author to be too arbitrary and in 
some cases incorrect, but are useful as a guide. There are many 
things to be considered in fixing the lowest and highest safe 
temperatures for perishable goods, chief of which are : First. — 
Initial temperature of goods when loaded into car. Second. — 
Temperature to which exposed en route. Third. — Time on the 
road. Other conditions, like ripeness of fruit and variety, have 
much to do with the temperature it will withstand without in- 


;The — sign denotes temperature below zero Fahrenheit.) 

Perishable Goods. 

Lowest Outside 


-C.5 "^ at: 

How Packed. 

Ale, ginger 

Apples, in barrels i 

Apples, loose | 

Apricots, baskets 

Aqua ammonia, barrels. . 

Asparagus • 

Bananas | 

Beans, snap 


Beef extract 

Beer or ale, kegs ' 

Beets I 

Bluing I 

Cabbage, early or latc..| 

Cantaloupes j 

Carrots j 

Catsup ' 

Cauliflower | 


30 20 

20 ! 10 

28- 15 

35 1 24 

30 : 20 

28 I 22 

501 32 

32 ' 26 
Zero —20 

25 I 15 
32, 20 

26 I 20 








10 Zeroi 


— 10 






— 10 









— 10 









Covered with straw. 
Packed in straw. 

In boxes covered with moss. 
In boxes with straw. 
In barrels or crates. 
Shipped loose. 

In manure and shavings. 
In crates. 
> Barrels or crates. 

In barrels with straw. 
Packed in crates. 



(The — sign denotes temperature below zero Fahrenheit.) 

Perishable Goods. 

I Lowest Outside 

1 ' ■ I "^ i o i^ 


1/1 3 

How Packed. 


I « 



Clam broth and juice.. 

Clams in shell 





Cymlings, or squashes. 

Deer I 

Drugs (non-alcoholic) . . 
Eggs, barreled or crated 


Extracts (flavoring) .... 


Fish, canned 




Groceries, liquid 


Kale ; 

Leek ' 

Lemons , 

Lettuce , 

Lobsters ' 


Medicines, patent ' 

Milk 1 

Mucilage ; 

Mustard, French I 


Olives, in bulk I 

Olives, in glass , 



Oysters, in shell . . . 
Oysters, shucked . . . 







30 I 

20 I 


10 Zero 
28 , 20 
32 20 
32 I 22 
Zero — 20 
32 I 28 
30 I 20 
10 Zero 
20 I 15 
10 (Zero 
18 ' 15 

— 10 
— 10 







I 65 


35 ■ 

20 I 


15 Zero 
28 ! 20 











— 10 




Zero 75 


Zero 75 
— 10 

In barrels. 

In barrels or crates. 

In baskets and barrels. 

In boxes with moss. 
In crates. 
Shipped loose. 

In boxes or crates. 

In barrels always iced. 

Packed in moss. 
Packed in cork. 

I In boxes or crates. 
I In boxes. 
In boxes or crates. 

In boxes. 
In sawdust. 

— 10 



In baskets or boxes. 
In barrels. 

80 In barrels or crates. 
80 In baskets, barrels or crates. 
65 In barrels. 
70 Do. 
75 In baskets. 
70 In baskets or barrels. 
65 In bunches in boxes. 
. . .. I In barrels. 





(The — sign denotes temperature below zero Fahrenheit.) 

Perishable Goods. 

Peaches, fresh, baskets.. 

Peaches, canned 

Peas : 

Pickles, in bulk 

Pickles, in glass 



Potatoes, Irish 

Potatoes, sweet 




Shrubs, roses or trees . . . 




Tea plants 


Tomatoes, fresh' 

Tomatoes, canned 

Turnips, late 

Vinegar, barrels 


Waters, mineral 

Wines, light 

Wild boar 

Wild turkey 


Lowest Outside 
Temperature. 60 








28 i 




•rtU J; c 

C « S I ^ -i 






— 20 


— 10 










— 10 















How Packed. 

In baskets or barrels. 
In barrels*. 

In barrels or crates. 
In boxes with paper. 
In barrels or baskets. 

In baskets. 

In barrels and sacks. 
In canvas or sacking. 
In barrels or crates. 

In boxes. 
In boxes. 
In small baskets. 

In boxes. 
In barrels. 

In barrels or in bulk. 

Shipped loose. 




A cold Storage house may be successfully cooled by ice 
mixed with a small proportion of salt. Many persons who em- 
ploy ice in an ordinary refrigerator or otherwise, are perhaps 
not fully aware that it may be employed with entire success for 
practical cold storage, even when placed in direct competition 
with the ammonia or other mechanical systems. In the city of 
IMinneapolis are seven concerns who employ refrigeration oper- 
ated under the author's systems^ aggregating about 400,000 cubic 
feet of storage space, which is cooled by ice, and ice mixed with 
salt. These houses are successfully competing for business with 
other houses equipped with the ammonia system, and are car- 
rying goods admittedly equal to the very best. Temperatures 
as low as from 10° to 15° F. are maintained in the freezing- 
rooms, and eggs are held at 30° F. with a pure and dry atmos- 
phere. These facts should establish beyond a question the possi- 
bilities of ice in the cold storage field. The system of natural ice 
cold storage which will produce these results is fully described 
further on in this chapter. Numerous plants are in operation else- 
where which use manufactured or artificial ice with a small ad- 
mixture of salt as a primary refrigerant. Artificial ice is as use- 
ful for this purpose as natural ice and for small plants is very 
desirable as compared with a small ice machine. 

The immense natural ice crop is, for the most part, consumed 
in the temporary safe keeping of perishable products, which are 
stored in the common house refrigerator or the larger refrigerator 
of the retailer. Many cold storage houses utilizing natural ice 
are in operation, which give more or less satisfactory results: 
generally the latter. Some persons have an idea that a cold 
storage house is a room with sawdust-filled walls with ice in it, 
but there are many points about cold storage not understood by 


the average person. It is the purpose in this chapter to discuss 
the various methods of cold storage by means of ice so that 
the careful reader may discriminate between them and under- 
stand the underlying natural laws. 

In discussing ice cold storage, it may be admitted at the out- 
set tliat the use of ice in any form for the preservation of food 
products, like eggs, butter, cheese and fruits, for what is known 
as long-period storage, has fallen into disrepute, owing to defects 
in the older systems. There are reasons for this, although the 
idea that the ammonia system is so much superior has been carried 
to an extreme not warranted by the existing facts. The real 
reason why the ammonia system has a better reputation is that 
natural ice has usually been misapplied to the work of cold storage, 
that is, it has been improperly used. The problem of cooling stor- 
age rooms by utilizing the stored refrigeration of the winter 
months in the form of natural ice has had the attention of many 
persons, among them the author and his father before him. The 
author's father always said that "expensive steam-driven ma- 
chinery could not successfully compete wath God Almighty and 
a Minnesota winter" in creating refrigeration. With this as a 
principle the Cooper system has been developed. Several sys- 
tems had previously been developed with varying success, but it 
is believed that up to the time the "Cooper System Gravity Brine 
Circulation" was first put in service, no system was in existence 
which could successfully compete with the ammonia or other 
mechanical systems. 

The use of ice as a refrigerant was long antedated by the 
use of natural refrigeration, which may be obtained in cellars 
or caves. It is well known that at a depth of a few feet below 
the surface, the earth maintains a comparatively uniform temper- 
ature of about 50° F. to 60° F. during all seasons of the year. 
This temperature varies somewhat, but above would cover a 
great majority of cases in any northern latitude where snow falls, 
and as compared with a summer heat ranging from 70° F. to 90° 
F. it will be readily observed that this natural low temperature 
of the earth is of considerable service in retarding decay and the 
natural deterioration of perishable products. By digging beneath 
the surface of the earth a cellar was formed which would produce 
results in refrigeration which were quite satisfactory during the 


early history of the perishable goods business, but would hardly 
withstand the critical test to which goods from modern cold 
storage houses are subjected. With the advent of the natural 
ice trade, ice came into use for household and other refrigerating 
purposes. Ice is at present and zmll probably alivays remain the 
most practicable m^ans of placing concentrated refrigeration at 
the disposal of the comparatively small consumer. It seems that 
prior to the nineteenth century the great cooling effect to be ob- 
tained from a small quantity of ice was not known nor appreciated 
by the world at large. The preservation of natural ice was like- 
wise not thought practicable for a time sufficiently long to allow 
of its use as a cooling agent during the heat of summer. With 
a knowledge of the cooling power possessed by the earth during 
warm weather the first ice houses were constructed below ground, 
without provision for drainage. The result of such an arrange- 
ment is easy to understand. Now ice men are careful to build 
above ground and provide good drainage as being necessary to 
the successful keeping of the ice. The first ice house did not 
provide protection for the ice, other than a roof overhead; all 
ice houses now employ sawdust or some other non-conductor of 
heat to protect the ice from contact with the air, and prevent 
the penetration of heat. Ice stored in the underground ice houses 
was mostly melted by July, while ice stored in a modern ice house 
may be kept until fall with a meltage of only ten or fifteen per 
cent. The evolution of the modern ice house from the under- 
ground pit has been gradual, and was not made all in one jump. 
It seems remarkable that the loss from meltage m the house is 
now so little, and this is accounted for only by considering the 
tremendous amount of refrigeration which is stored up in a 
small quantity of ice, and a knowledge of proper means for pro- 
tecting same. (For further information on ice harvesting and 
storing and the construction of ice houses, see separate chapters 
on these subjects.) 

The refrigerating value of ice as compared with an equal 
weight of cold water at 32° F. is as 142 is to i. That is, ice has 
142 times as much cooling power in passing from ice at 32° F. 
to water at 32° F., as an equal weight of water in passing from 
32° F. to 33° F. It has perhaps been noticed that ice forms quite 
slowlv even in extremelv cold weather. This is because the water 

ither Bit re a 


I„ tlK- foll-O"- 

,oiit in j "*->'- 

,e cases i^-»<=«x > 

Jury. A 


,h»lile <^o« 

Apricots. ba^l^<^^ 


3eaTis, snap 
15car ■ ■ - - ; 
[Beef extract 
[Beer or ale. 

lieets * 

3liihig - - * ' 

CTarrots - 



res are about 36° F. to 38° F. during warm 

fitKly crushed ice with a small proportion of 

le ice is hastened, and a much lower temper- 

- caused by the great affinity which salt has 

^ilt comes in contact with ice this property 

Li:t the water from ice rapidly, reducing it from 

M, causfin^^ a rapid production of refrigeration 

1 rption of heat. A pound of ice will do a given 

i: in refrigeration regardless of whether it is 

at 32'' F. or at some lower temperature in com- 

ilt. The lowest temperature obtainable with a 

:e and common salt is slightly below zero, Fahren- 

directly in the mixture. A room cannot be cooled 

IS witl) ice and salt. By using chloride of calcium 

tth crushed ice a temperature many degrees below 

kbtained. This salt costs about double what common 

1 is not at present in use for freezing purposes. A 

111 designed by the author was cooled to a tempera- 

\, with the gravity brine system, and held for a few 

• >nstrate the possibilities of ice and salt refrigeration. 

itures of 12"* F. to 15° F. are easy to maintain, and at 

ively small expense. 

.^mre in cold storage rooms has been the source of much 

n and solicitude among cold storage operators, and a 

-e of the action of this condition in rooms artificially 

ind its relation to temperature, will assist in our present 

When a storage room is cooled by ice only, the higher 

i^erature at which the room is held the dryer will be the 

!cre, and the better will be the circulation. This state- 

L^^eneral, and may be modified by exceptional conditions. 

vHltTately dry air and a good circulation are necessary to 

'^ssful cold storage, but with these two conditions must go, 

n imperati%^e adjunct, a low temperature if good results are 

*(^ obtained. It has been stated already that the lowest de- 

lable temperature with ice only was 36° F. to 38° F. Com- 

iiively few products are now stored in a temperature above 

}2' F. to 34^ F.t and a large bulk of the business is handled at 

'I temperature ranging from 30° F. to 32° F. It is therefore 

vident that ice alone will not produce temperatures sufficiently 


must give up a large amount of heat before it will become ice. 
The natural bodies of water are quickly reduced in temperature 
to about the freezing point by a cold spell of weather in the fall, 
but the freezing of the water into ice at the freezing point (32° 
F.) is quite a diflferent matter. This natural phenomenon is ac- 
counted for by what is known as latent heat. It is this latent 
heat in water which makes it so slow to freeze, and when once 
frozen, makes the ice so slow in melting, as the same latent heat 
which is given off in freezing must be absorbed from surrounding 
objects before the ice will melt into water. To fully understand 
this it is necessary to become familiar with the unit of measure- 
ment used in determining quantity or amount of refrigeration 
produced by melting ice, and the relation between heat and cold. 

Heat is a positive quantity, that is, possesses character, so 
to speak, while cold is simply the absence of heat. It follows, 
therefore, that any unit of measurement applicable to heat will 
also measure refrigeration. If heat is extracted from any object 
it becomes cold, and it becomes cold in exactly the same amount 
or proportion as the heat is absorbed. The quantity of heat ab- 
sorbed is measured by the British Thermal Unit, generally ab- 
breviated to B. T. U. One B. T. U. is equal to the raising in 
temperature of one pound of water one degree, as shown by an 
ordinary thermometer. The standard American thermometer 
is named after its originator, Fahrenheit, and measurements by 
this thermometer are usually abbreviated to a simple F., to dis- 
tinguish from some other thermometers in use. In writing tem- 
peratures the F. is placed after the degree mark. We would sav 
then that one pound of ice in changing from ice to water at 32"* 
F. absorbs 142 B. T. units. When a pound of water is raised in 
temperature from 32° F. to 33° F., only one B. T. U. is absorbed. 
In other w^ords ice in melting has 142 times the refrigerating 
value that the same weight of water has when raised in tem- 
perature 1° F. This latent heat of liquefaction, as it is called, 
explains why ice melts so slowly, and why a comparatively small 
quantity will perform such a large refrigerating duty. 

When used for cold storage purposes, the temperatures ice 
alone will produce are limited. As the melting point of ice is 
32° F., the temperature which can be obtained in a room cooled 
by ice only must necessarily be somewhat higher. The lowest 


practicable temperatures are about 36° F. to 38° F. during warm 
weather. By mixing finely crushed ice with a small proportion of 
salt the melting of the ice is hastened, and a much lower temper- 
ature results. This is caused by the great affinity which salt has 
for water. When salt comes in contact with ice this property 
causes it to extract the water from ice rapidly, reducing it from 
a solid to a liquid, causing a rapid production of refrigeration 
or rather the absorption of heat. A pound of ice will do a given 
amount of work in refrigeration regardless of whether it is 
melted naturally at 32° F. or at some lower temperature in com- 
bination with salt. The lowest temperature obtainable with a 
mixture of ice and common salt is slightly below zero, Fahren- 
heit. This is directly in the mixture. A room cannot be cooled 
as low as this with ice and salt. By using chloride of calcium 
salt mixed with crushed ice a temperature many degrees below 
zero may be obtained. This salt costs about double what common 
salt does, and is not at present in use for freezing purposes. A 
freezing-room designed by the author was cooled to a tempera- 
ture of 6° F., with the gravity brine system, and held for a few 
days to demonstrate the possibilities of ice and salt refrigeration. 
Temperatures of 12° F. to 15° F. are easy to maintain, and at 
comparatively small expense. 

Moisture in cold storage rooms has been the source of much 
discussion and solicitude among cold storage operators, and a 
knowledge of the action of this condition in rooms artificially 
cooled, and its relation to temperature, will assist in our present 
study. When a storage room is cooled by ice only, the higher 
the temperature at which the room is held the dryer will be the 
atmosphere, and the better will be the circulation. This state- 
ment is general, and may be modified by exceptional conditions. 
A moderately dry air and a good circulation are necessary to 
successful cold storage, but with these two conditions must go, 
as an imperative adjunct, a low temperature if good results are 
to be obtained. It has been stated already that the lowest de- 
pendable temperature with ice only was 36° F. to 38** F. Com- 
paratively few products are now stored in a temperature above 
32° F. to 34° F., and a large bulk of the business is handled at 
a temperature ranging from 30° F. to 32° F. It is therefore 
evident that ice alone will not produce temperatures sufficiently 


low for the handling of a successful cold storage business. Tem- 
peratures sufficiently low can be obtained only by ice mixed with 
salt or by the use of refrigerating machinery. As before stated, 
in a room cooled directly from ice, the nearer the temperature of 
the storage room approaches the temperature of melting ice, 
the poorer will be the circulation, and the higher per cent of 
moisture the air will contain. Circulation of air within a stor- 
age room is caused by a difference in weight of air in different 
parts of the room. The air in immediate contact with the ice is 
cooler and heavier, and therefore falls to the bottom of the stor- 
age room. The warmer and lighter air at the top of the storage 
room at the same time rises to the ice chamber. As long as the 
difference in weight and temperature exists, circulation will take 
place. The principle underlying air moisture is quite compli- 
cated, but may be understood by a little study. It is well known 
that when warm, moist air is circulated in contact with a cold 
surface the moisture will be condensed upon the cold surface. 
This is illustrated by the so-called "sweating" of a pitcher of 
ice-water in warm, humid weather. This same action takes place 
in every cold storage room. When the room is cooled directly 
by ice the moisture contained in the comparatively warm air of 
the storage room is continually being condensed on the cold 
surface of the ice. As the air becomes nearer and nearer the 
temperature of the melting ice, less and less moisture will be 
condensed, and the air becomes in consequence more and more 
saturated with moisture. If it were possible to cool a storage 
room to 32° F. with ice melting at 32° F., the air of the room 
would be fully charged with moisture, and totally unfit for the 
storage of any food product. If a room is cooled to 35° F. with 
ice melting at 32° F. the per cent of moisture in the air would be 
91 per cent of what it would be if the room were cooled to 32** 
F. in the manner above indicated. If the room is cooled to 38® 
F. the air would contain 79 per cent, and if the room be cooled to 
40° F., it would contain 70 per cent. In actual practice these 
air moistures would be somewhat higher, owing to the presence 
of moisture which is continually given off by the goods in stor- 
age. Even the temperatures with their corresponding percent- 
ages of air moisture as here stated are know^n to be too high for 
the successful preservation of food products for long periods of 


three months and upwards, and even for shortei periods results 
will not be as perfect as with a dryer atmosphere and lower tem- 
perature. Further than this the circulation, temperature and 
humidity in a room cooled by ice only are largely dependent on 
outside weather conditions. The temperature will of course be 
higher during the hot weather of summer. The humidity is, 
as we have seen, controlled by the temperature of the air in the 
room, as is also the circulation. When the temperature outdoors 
during fall and winter is at or near the melting point of the ice 
in the storage room (32° F.) no circulation will take place. The 
air will become very damp and impure from the moisture and im- 
purities given off by the goods in storage, the goods will mold 
and decay rapidly. This is a condition to be met with in every 
house which is cooled by placing natural ice in direct contact 
with the air of the storage room. (For further information on 
the relation between humidity and air circulation see separate 
chapters under these headings.) 


Reasons have been given why natural ice, as generally used, 
will not produce satisfactory conditions for the storage of food 
products for long periods. This information will enable the 
reader to fully understand the weak as well as the strong points 
of the various systems here described which utilize ice as a re- 
frigerant. Ice alone may produce useful and even satisfactory 
results if the goods need only to be carried for a period of one, 
two or even three months, but where it is desired to erect a build- 
ing with the idea of handling a variety of products for long 
storage and with intention of building up a permanent business, 
the old primitive methods of overhead, or side, or end ice, will 
result in disappointment and loss. This has been the history of 
at least nine-tenths of the public cold storage warehouses cooled 
in this way. If those who contemplate embarking in the business 
cannot build a house which will carry the various products suc- 
cessfully, it is better to keep out of the business altogether. The 
author has had occasion to remodel and even tear down cold 
storage houses in which ice was the only refrigerant, and in not 
a single instance known, has a house, operated in this way, been 
able to build up a substantial and profitable business for its 



owner. Quite a number of such houses are now in use, and a 
few are being put up at the present time, but they are mostly 
operated for private use for one or two products only, and for 
comparatively short time storage. They do not give successful 
results when used for sensitive goods like butter and eggs. 

The first application of natural ice to the preservation of 
food products was that of placing goods directly in contact with 
the ice, in a similar manner to the method now employed in ship- 
ping fish or poultry or in cooling melons for temporary holding. 
This method can be employed for but few products, because 
the goods become wet and water soaked. The air in such a 

:v/V//////^//////// //////y/////////////^^^^ 





E0 3E 5EC^'0^ 

LO.iGiTvyD'nflt, sccrro/i 


chamber has not the benefit of the purifying and drying influence 
of circulation, and goods in condition favorable for such action 
mold and decay rapidly. As an improvement on this method, 
it was natural to separate the goods from the ice, by placing the 
ice at one end or side of the chamber and the goods at the other, 
and not in contact with each other. The wetting of the goods is 
thus avoided, but when the goods are not placed in contact with 
the ice, they are of course carried at a somewhat higher temper- 
ature. No circulation of consequence is present, and the air be- 
comes moist and impure very rapidly. Improving on the side or 


end icing plan, a two-compartment refrigerator was constructed, 
with the ice above and the goods to be preserved stored below. 
By providing openings for the flow of cold air from the ice down 
into the storage compartment, and for the flow of comparatively 
warm air up into the ice compartment, a circulation of air was 
produced, which was the first really important principle discov- 
ered in cold storage work. Air is purified and dried by circula- 
tion under proper conditions. The reason for this is discussed 
in the chapter on "Air Circulation." The first successful ice cold 
storage houses were built with ice above the storage chamber, 
and a large majority of those still in use are of this general plan, 
with, of course, many modifications. As before stated, they are 
useful mostly for short-time storage. When placed in competi- 
tion with a house equipped with a system which gives positive 
control of circulation, moisture, temperature and purity of the 
atmosphere, they soon lose business and fall into disuse. Many 
patents have been issued on the various systems of ice cold stor- 
age. A few only of those systems which have come to the au- 
thor's attention will be briefly described, with the idea of show- 
ing the development of ice cold storage, and also that the reader 
may form some impression as to the relative merits and weak 
features of the different systems which have been more or less 
prominent rn the past. 

The Fisher System. — One of the oldest systems of ice cold 
storage and one on which many houses have been erected, is the 
"Fisher System," (See Fig. i.) The points of this system 
which are covered by patent are not known to the author, but the 
main essentials of the houses as constructed by Fisher, were an 
ice chamber located above a storage room with an insulated 
waterproof floor separating the two. Openings were provided 
for the circulation of air from the ice chamber to the storage 
room, and flues from the storage rooms to the top of the ice 
chamber. One who is familiar with the operation of this system 
says that Fisher's houses, when new, would do fair work, but 
when they became old the results were very bad. None of these 
houses known to the author is now in operation. The principle 
was very simple, and as good results might be obtained by this 
system as with a majority of the later ones using ice only. 



The Wickes System. — The **\\'ickes System" has been 
largely introduced among certain lines of trade, more particularly 
in the refrigerator car service. It is claimed that several thou- 
sand of the Wickes cars are in constant service. The Wickes 
company some years ago installed a number of cold storage 


plants, but it is believed that they do not now recommend their 
system for such use. The devices which make up the Wickes 
system (see Fig. 2) consist of a basket-work ice bunker, com- 
posed of galvanized iron strips. Attached to the strips where 
the air flows into the ice bunker are projecting tongues, which, 
it is claimed, give largely increased cooling and moisture-absorb- 



ing surface, which dry and purify the air more thoroughly. 
Where the air flows out at the bottom of the ice bunker, it passes 
down over a network of galvanized wire, w'hich is kept cold and 
moistened by the water dripping from the melting ice above. 
These devices which have been added to the ordinary construc- 
tion of the ice box no doubt add somewhat to the efficiency of the 
system, but are scarcely worth their cost. Any system like the 
Wickes, employing side or end icing, must be greatly inferior 
to the overhead ice system, because the circulation of the air 
becomes stagnant when the ice is reduced in the ice bunker. The 
temperature also rises under these conditions, and unless a very 



large ice bunker is provided and the supply of ice fully main- 
tained it is not possible to produce as low temperatures as with 
an overhead ice system. 

The Stevens System. — A good many houses have been 
erected on what is known as the "Stevens System." (See Fig. 
3.) This differs somewhat from other systems of overhead icing 
in having an arrangement of fenders and drip troughs forming 
an open pan over the entire floor of the ice room, except at the 
ends and sides, which are left open for the flow of warm air up- 
ward from the storage room. The cold air from the ice works 
down through the open pan. The pan is formed by a series of 



gutters suspended between the joists and capping pieces over 
the joists to cause the water to drip into the gutters, at the same 
time allowing a circulation of air between gutters and capping 
pieces. Those who have used the system state that trouble re- 
sulted from spattering of water from the troughs. This sys- 
tem has the advantage of maintaining fairly uniform tempera- 
tures, regardless of the amount of ice in the ice chamber. Quite 
a number of these old houses are still in use. The results obtain- 


ice cnnMBcn 


J • V 



able are not essentially different from those to be had by other 
overhead ice systems. 

The Nyce System. — The system invented by Professor 
Nyce is one of the old-timers still to be found in use. In this 
system (see Fig. 4) the cooling effect of melting ice, and the 
drying and purifying effect of chloride of calcium, are depended 
upon to produce the desired result. It is an overhead ice system, 
but the air is not circulated from the ice chamber into the stor- 
age room. The storage room is cooled by contact with the met- 



allic ceiling of the storage room, which also forms the floor of 
the ice chamber. Professor Nyce no doubt studied out this sys- 
tem from having observed the bad effects which result in the 
ordinary overhead ice cold storage during cool or cold weather. 
To absorb the moisture which is given off by the goods and 
from the opening of doors, the well-known drying qualities of 
chloride of calcium were used. The results obtained by cooling 
and drying a room in this way were quite satisfactory, and com- 
pared favorably with any of the other ice systems in general use. 


The patents on this system have long ago run out, but the sys- 
tem was not sufficiently successful to encourage its general use, 
and so far as known, no new houses of this kind are being built 
at present. 

The Jackson System. — ^The "Jackson System" of overhead 
ice cold storage is one of the most general in use, and it is 
claimed that over three hundred houses have been constructed. 
The system (see Fig. 5) is extremely simple, and the chief 
patent is on a removable pan suspended under an open ice floor. 


It is, of course, an overhead ice system, with air circulating from 
the ice chamber down into the storage room. The spaces be- 
tween the joists supporting the ice are left open, and aprons of 
galvanized iron protect the girders which support the joist, and 
conduct the drip to the removable pans before referred to. In 
some cases cylindrical tubes or tanks of* galvanized iron are pro- 
vided. These are filled with ice and salt for the purpose of re- 
ducing the temperature still lower than is possible with the ice 
alone. The use of tanks in a room provided with a circulation of 
air from the ice cannot result in any great benefit to the rooms, 
as the circulation is retarded or stopped, and a pollution of the 
air results to a considerable extent. Tanks of diflferent shapes 
and sizes are used in a number of systems, and will be considered 
by themselves in another paragraph. The "J^^^son System," so- 
called, is principally a pan hung below the ice joist so as to pro- 
mote a circulation of air from the ice chamber into the storage 
room. Other devices as simple will accomplish the same result. 
Nothing new of consequence has been added to this system for 
a number of years, but a few houses are being installed on this 
plan, largely because it has been advertised and pushed in former 

The Dexter System. — The Dexter patents cover a much 
more complicated apparatus than any system or prior invention 
which utilizes ice as a refrigerant. The "Dexter System" of in- 
direct circulation is a very ingenious device. (See Fig. 6.) It 
consists of a series of air flues between the exterior and interior 
walls of the cold storage room. The cold air from the ice cham- 
ber flows down through one set of flues, and as it is warmed 
returns through another set located outside of the first set. This 
effectually prevents the penetration of outside heat, and makes 
the regulation of temperature comparatively easy, even in warm 
weather. This is practically like putting one cold storage room 
inside of another. Dexter uses also the galvanized tubes or 
tanks filled with ice and salt for bringing down the temperature 
to the desired point. The circulation of air widiin a room cooled 
in this way is sluggish, and the air too moist for most products 
which are generally placed in cold storage for safe keeping. 
Dexter also has patents on a method of circulating air from the 
ice chamber down through or around tanks filled with ice and 



salt, into the storage room, but the writer is not aware that these 
devices have proven to be possessed of any particular merit or 
that they have been brought into general use. Other patents 
have been taken out on a scheme for constructing an ice floor or 

| p/////////////y//w^ 


•W//m/W///////77f/ A 















pan. This has been found leaky in a number of cases, and has 
been removed and built over. Still other patents are on a system 
of ventilation, and a method of insulating the ends of joist where 
they enter the walls of a building. 

Any system of cooling storage rooms in which the air is 
circulated directly from the ice has the constant trouble with 



dampness of the ice room or bunker. Moisture always con- 
denses on the ceilings or side walls of the ice receptacle, and mold 
results ver>' soon. The air circulating over the molded surface 
carries mold spores into the storage room. The goods stored 
therein suffer in almost every case. A house which has been 
in service for some time may be very bad in this respect, espe- 
cially during cool weather of fall or early winter, as the temper- 
ature is lower and the air of storage room more moist. Damp- 
ness of ice room also causes decay of woodwork and insulation. 

The Direct Tankage System. — There are or have been a 
number of cold storage houses, cooling rooms and freezers re- 
frigerated by what the author calls the "Direct Tankage System." 
This system consists simply of placing metal receptacles filled 
with ice and salt in the room to be cooled. There are several 
forms of tanks in service, the more common of which are the 
square cornered or rectangular tanks, the thin tanks, or what are 
sometimes called "freezing walls,'' and the cylindrical or round 
tanks. Usually these tanks are made of galvanized iron. They 
may be made of a thickness of iron ranging from gauge i8 to 
gauge 24 metal. Gauge 20 iron is usually the best to use. These 
tanks are almost invariably filled from the top through the ceil- 
ing, or what would naturally be the floor of the room above. 
They have, however, in some extreme cases been filled from the 
side, either from without or from within the room. 

The rectangular or square tanks, as at first employed, have 
gradually gone out of use, because they are difficult to make 
and keep in shape and, as built in a number of cases, were so 
large that the meltage of ice w^ould be largely near the tank sides, 
and very little towards the center. Tanks of this class have been 
used which were as large as three feet in their smallest dimen- 
sion, and as the meltage was almost entirely within eight or 
ten inches of the outer surface, the waste of space and lack of 
economy are at once apparent. 

The thin or flat tanks, which are sometimes called "freezing 
walls," as usually constructed, are only about four to ten inches 
in thickness, and are sometimes narrower at the bottom than at 
the top. These of course are iced from the top, and many fish 
freezers, built years ago, did good service w'hen equipped in this 
manner. One serious objection was that only one surface of the 


tank was available to any considerable extent for cooling service, 
as the back or that portion of the tank near the wall received 
comparatively little air circulation, in fact, in many cases the back 
of the tank was placed directly against the wall of the room with 
no space left between. The construction of these tanks, also, is 

Furthermore, any flat surface when used for a purpose of 
this kind has a tendency to bulge outward, owing to the pressure 
of the ice and salt within. The result is that the tanks become 
leaky and will rust out rapidly. 

The cylindrical tanks are very much the best of the three 
kinds mentioned. They are easy to make, and owing to the 
cylindrical shape will not readily get out of order and are 
much more practical than either the freezing walls or the rec- 
tangular tanks. It has been found in actual practice that in 
producing refrigeration through a metallic surface from the 
meltage of ice, where one side of the metal is exposed to the air 
of the cool room, and the other has ice and salt in direct contact, 
comparatively little refrigerative effect is obtained from the ice 
lying more than six inches away from the exposed metallic sur- 
face. Cylindrical tanks, therefore, have been built of a diameter 
of eleven inches, that being a size readily constructed mechanically 
and one which will give best results when used for freezing or 
ccK^ling. In the illustration of the Dexter System (page 449) 
may be seen the cylindrical tanks suspended from the floor of 
the ice chamber. 

The direct tankage system, while it has been in use quite 
extensively, is not at present being installed to any great extent, 
as its disadvantages are many. The nastiness and muss occa- 
sioned by the icing of tanks through the ceiling of the storage 
room is in itself sufficient to condemn the system. The contin- 
uous slop resulting from handling the ice and salt upon the floor 
above the storage room will result in the rotting and decay of 
timbers and insulation in a comparatively short time. It will 
also readily be seen that the great amount of space wasted by 
thus icing the tanks is a serious drawback to this system. Prac- 
tically nearly as much space is required for the mere charging 
of the tanks as is available for refrigerating purposes. Another 
disadvantage of the direct tankage system is that it is wasteful 


of space in the storage rooms, as the tanks do not present as much 
surface to the air of the room proportionately as does iron piping 
in the form of coils. The tanks in the room are also sloppy and 
wet and the pan underneath is liable to become choked up and 
overflow on the floor of the storage room. Further than this it 
is extremely difficult to regulate the temperature of a room with 
this system, owing to the fact that there is no control or balance 
on the refrigerating eflfect. Directly after charging the tanks, 
the temperature will run down and then slowly rise until the next 
time of charging. The author has worked with this system for 
a number of years and has abandoned its use entirely in favor 
of the gravity brine system cooled with ice and salt, which is 
described further on in this chapter. 

Mr. J. A. Ruddick, Chief Dairy Division, Department of 
Agriculture, Ottawa, Canada, has this to say regarding the dis- 
advantages of the direct tankage system : "I am doubtful, after 
some years' experience, if it is the best system to recommend. 
The cylinders are not always kept full, causing insufficient and 
irregular refrigeration, and excessive dampness is likely to result 
because of insufficient air circulation or because of the moisture 
from the cylinders whenever the ice is allowed to melt off the 
outside of the cylinders." 


These various systems of ice refrigeration which have come 
into general use during the past thirty-five years, have been briefly 
outlined and commented on by the author, so that the reader 
may comprehend, roughly, the history of and the reasons why 
ice refrigeration has not given satisfaction when placed in 
competition with the mechanical systems which are now gen- 
erally understood to be the best for all purposes. It is now 
necessary for us to make an investigation of the "ammonia" or 
** mechanical" system, when applied to cold storage, in order to 
ascertain in what vital particular this system surpasses the old- 
time ice systems. In visiting such a cold storage warehouse, we 
find a building with insulated walls not differing from those of 
an ice cold storage. The interior we find divided by insulated 
partitions into separate rooms for various products; goods hav- 
ing a strong or disagreeable odor being carefully isolated from 


delicate goods like butter and eggs. In this respect the ammonia 
cold storage has the advantage over the old style ijce cold storage, 
as the latter, even if divided into different rooms, generally has 
an ice chamber common to all, making contamination of one 
product from another probable. Each room of an ammonia cold 
storage is equipped with a coil or coils of piping placed on the 
walls or any convenient location. Through this piping flows a 
liquid or a gas at a low temperature. This cools the piping, 
which in turn cools 'the air of the storage room. The surface 
of the pipe being at a low temperature, frost accumulates on the 
pipe. This frost is moisture which is taken from the air of 
the room. The low temperature of the pipe thus causes a con- 
stant drying of the air of the room. The main difference be- 
tween a room cooled in this way and one cooled by ice, is that 
it is much dryer, because cooled by frozen surfaces at a tempera- 
ture which will collect moisture from the air of the room in the 
form of frost. In three houses out of four, no circulation of air 
is provided for, nor means for supplying fresh air. If we pursue 
our investigation further and enter the machine room, we find 
a complete steam plant, with which we are all fairly familiar, 
and much other machinery and apparatus besides, which takes a 
bright engineer some time to successfully master in all its de- 
tails. This, then, is the average "ammonia" cold storage, as seen 
by an outsider. The real and only reason why such a plant pro- 
duces better results than the average ice system, aside from a con- 
trol of temperature, may be summed up in the two words "DRY 
AIR." It is now purposed to describe a system which has all 
the advantages of the ammonia system in the respect of pro- 
ducing a dry atmosphere in the storage room, and yet has the 
advantage of the ice systems in being simple to operate, econom- 
ical and sure against breakdown. 


It has already been pointed out that it is impossible to pro- 
duce a dryness or humidity of air in a cold storage room cooled by 
ice, beyond a percentage which is fixed by the temperature of the 
room. That is to say, practically no control of humidity is possi- 
ble in such a room. Further than this, the air in an ice-cooled 
room is almost invariably moister than in a room of the same tem- 


perature cfx^lecl by pij>e surfaces. In a room cooled by frosted 
pipe surfaces, the moisture which is given off by the goods, and 
that which finds its way into the room when doors are opened 
or otherwise, is frozen on the pipes in the form of ice or frost. 
This is because the pipes have a temperature below the freezing 
pomt of the moisture in the air. causing the nwisture to freeze on 
the surface of the pipes, and leading to a greater drying of the air 
than where ice is the cooling agent. Xot only uill pipe surfaces 
at a temperature below the freezing point of the air moisture 
produce a dryer room, but they will also produce a lower tem- 
perature, and make the control of temperature possible. It has 
already been stated that the reason why the ammonia cold stor- 
age houses produced better results aside from a control of tem- 
perature, was their ability to give a dryer air. A system which 
will utilize natural ice as a primary refrigerant and yet give a 
dry air and low temperature, would then necessarily be able to 
compete on an even basis with the ammonia or mechanical sys- 
tems of refrigeration. 

With a due appreciation of the facts as stated above, there 
was begun a series of experiments to demonstrate the possibilities 
of ice refrigeration, and the refrigerating apparatus now known 
as the Cooper system is the result. At the time of beginning these 
experiments, the house experimented with was a nearly new one, 
equipped with what was supposed to be the very best and latest 
system of ice refrigeration (Dexter System), and at that time 
the writer was familiar with nearly all the prominent systems 
of ice cold storage, as already described. It was thought that 
if brine cooled by the ammonia system and circulated through 
pipes for cooling storage rooms would give better results than 
ice, the same results might be produced by cooling brine with a 
mixture of ice and salt, and circulating the brine through pipes in 
the same way. To demonstrate the practicability of the idea, a 
small room was fitted up for a test. An insulated tank was con- 
structed, in which was placed a pipe coil surrounded by ice and 
salt. Another coil was placed on the wall of the room, and the 
two connected together. A pump driven by an electric motor, 
caused the brine to flow from the coil in the tank through the 
coil on the wall, and then again through the tank coil continu- 
ously. A temperature of brine ranging from 12° F. to 18** F. 



was readily obtained, and the experiment was such a marked 
success, even with this crude apparatus, that it was extended 
to two other rooms, larger than the first. This time the pipes 
were so arranged that a partial circulation of brine would take 
place without the operating of the pump, but still another trial 
was necessary to fully demonstrate that the system could be 
operated entirely without a pump; that is, by the natural or 
gravity circulation of brine. This was obtained in a manner 
similar to the circulation of water in the hot water heating systems 


fig. 7. — diagram showing arrangement of brine coils in 
cooper's system. 

used in heating buildings. In the gravity brine system, the tank 
which contains the ice and salt, and the tank coils or primary 
coils, as they are called, are located at a higher level than the 
secondary coils which do the air cooling in the rooms. Fig. 7 
shows the arrangement of coils in use. When the tank is filled 
with ice and salt, the brine standing in the primary or tank coil 
is cooled by contact with the ice and salt which surrounds the 
pipes, to a lower temperature than the brine contained in the 
secondary coils, and consequently flows down into the secondary 


coils. At the same time the brine from the secondary coils rises 
into the primary coils, where, as it is coolecj, it repeats the circuit 
in the direction shown by the arrows. The term "gravity," as 
applied to this system of brine circulation, refers to the cause 
of circulation which is owing to the difference in specific gravity 
(weight) between the cold brine in the primary coils and the com- 
paratively warm brine in the secondary coils. The temperature 
of the circulating brine will range from 5° F. to 20° F. It is com- 
paratively easy to cool a room to 10® F. or 15° F. with the 
gravity brine system. As a matter of experiment, a room was 
cooled to 6° F. for a short time. The brine which circulates in 
the primary and secondary coils is usually a solution of chloride 
of calcium, which is used in preference to common salt brine for 
the reason that it rusts the pipes less and will not freeze as 
readily. The circulating brine is entirely independent of the 
brine which runs out of the tank as a result of the mixture of 
ice and salt. The refrigeration in the waste brine is utilized 
for cooling purposes by running it through a coil of pipe of 
suitable size at any convenient place in the building, and it is 
afterwards led to the sewer. The chloride of calcium brine, 
on the other hand, remains always in the pipes, the only loss 
being from leakage, which is, of course, very small. It will be 
appreciated, by experienced persons, that this system of cooling 
is simple in principle, very unlikely to get out of order, and when 
once in operation, will continue as long as the supply of ice and 
salt is maintained in contact with the primary coils in the tank. 
In operation it is usually necessary to fill the tank but once each 
day witli ice and salt, and the circulation will remain continuous 
and automatic through the twenty-four hours. The ice in the 
tank will melt down one to four feet per day, depending on how 
hard tlie apparatus is being worked, and it is only necessary to 
refill with enough ice and salt to keep the tank full. (See direc- 
tions for operating further on in this chapter.) 

Rooms cooled by the gravity brine system are subject to pre- 
cisely the same drying and purifying influences as are rooms 
cooled by any of the mechanical systems of refrigeration. The 
moisture and impurities in the air are, to a great extent, frozen 
on the surface of the pipes, and temperatures are easily con- 
trolled. In applying ice to cold storage work by this system, the 


ice has no more connection with the air of the storage room than 
if it were miles away. The ice is, in fact, generally placed in 
an ice room of cheap construction, built independently of the cold 
storage rooms. Where the ice room is already built, it is only 
necessary to build the cold storage rooms alongside of the ice 
house, equip them with cooling apparatus and means for getting 
the ice to the tank containing the primary coils. Even the loca- 
tion of ice house is not important. The cold storage house may 
be located in the center of the business district, and the ice on 
the ice field. The necessary quantity may be hauled each day. 
This is entirely practicable, and its feasibility has been demon- 
strated in several different localities. 

Except in plants of very small size, the ice is usually crushed 
and elevated to the tank by machinery. This saves much labor, 
and results in better work. The machine for crushing the ice 
is generally located at or near the floor of the ice room. 
The ice is fed into the crusher through a chute, which is made 
in sections. As the ice is worked down in the house, a section 
is removed to bring the top of the chute about on a level with 
the top of the ice. The ice is first chopped into irregular pieces 
of twenty or thirty pounds or less, then shoveled into the chute, 
which drops the ice into the crusher. From the crusher, in 
pieces not larger than a hen's egg, it drops into a bucket elevator 
which raises it to a point near the tank, and somewhat above it, 
where the elevator dumps the ice into an inclined tube terminating 
in a flexible spout. The flexible spout is pivoted, and will deliver 
ice to any part of the tank without shoveling. The only hand 
labor necessary on the ice is the chopping of the ice and shovel- 
ing it into the chute. Two men will easily handle four tons of 
ice an hour in this way. Four tons of ice a day will cool a stor- 
age house with forty carloads capacity, during average summer 
weather. The section. Fig. 8, on following page, shows the ice- 
handling apparatus in conjunction with the other parts of a fully- 
equipped storage house. It may be noticed that the storage rooms 
have no communication with the ice house, and that the cooling 
is effected by circulating the air of the rooms in contact with 
the secondary coils of the gravity brine system. 

The storage rooms are cooled and the temperature regulated 
directly by the gravity brine system. This may be done by placing 



the secondary coils of the brine system directly in the room, but 
a better method is by using the forced air circulation system, 
especially if the rooms are fairly large. For this purpose, the 



This diagram is for the purpose of showing the different systems clearly, but is not in 
good proportion, as the storage room is shown much smaller than it is. The apparatus is 
really quite small as compared with the rooms. 

secondary coils are placed in a room by themselves, known as 
the coil room. A fan draws the air from the coil room and dis- 
tributes it to all parts of the storage room. The air is returned 
to the coil room by being drawn off at the top of the storage 


room through a perforated false ceiling. Depending on various 
conditions, either perforated side air ducts or perforated false 
floors are used for distributing the air uniformly throughout the 
room. (In the chapter on "Air Circulation" are discussed the 
various phases of air circulation and the relation of refrigerating 
surfaces thereto, describing the various designs by the author for 
improving air circulation. See also chapter on ** Ventilation'' 
and ** Uses of Chloride of Calcium " for other simple devices 
which are installed in combination with the gravity brine system 
as illustrated in Fig. 8.) 


It has been thoroughly demonstrated by the author that 
tanks of a greater length than lo feet were usually unnecessary 
and the additional length when used was practically wasted. 
In practical operation ice in the tank does not settle or melt down 
generally, more than from one to three feet per day of twenty- 
four hours. All that is required, therefore, in the length of the 
tank is that it should be sufficiently long to allow the salt brine 
which is dripping down through the ice to become thoroughly 
diluted and expend its ice-melting power before reaching the 
bottom. While the largest amount of refrigerating duty is ac- 
complished where the ice and salt are in direct contact with one 
another, near the top of the tank, yet there is considerable re- 
frigerating value or ice-melting power in the brine which results 
from a union of the ice and salt. This brine trickles down 
through the finely crushed ice in the tank and has the same action 
on the ice as the salt, only to a lesser extent. As the brine be- 
comes more and more dilute, it has less and less value in this 
respect and finally possesses practically none, if the tank is of 
sufficient length. 

As before stated, the practical limit of length for the tank 
is ten feet, although for some purposes a length of twelve feet 
may give more satisfactory results. The author has had in ser- 
vice for freezing purposes tanks which were sixteen feet in 
length. With tanks of this length the meltage in the lower 
three or four feet is very small. In fact, the bottom six feet of 
these tanks will not do any considerable amount of work. The 


further down in the tank, the less meltage of ice there will be, 
depending on the temperature at which the room is being carried. 

The work of charging the tanks with ice and salt is compara- 
tively simple, but at the same time there is a chance for the ex- 
ercise of considerable skill and sound common sense. It is an 
old idea in connection with freezing ice cream that the ice and 
salt should be filled into the freezer in alternate layers instead of 
being thoroughly mixed together. There is no question at all 
but that this is a mistake. The more thoroughly the ice and salt 
can be mixed together, the better the freezing action to be ob- 
tained, and the greater the economy of ice and salt. 

If the ice and salt are filled into the tank in alternate layers 
there are two bad results which interfere with the practical and 
efficient operation of the plant. One is that the salt will cake 
and form lumps, which will probably go clear to the bottom of 
the tank without entirely dissolving ; another is that quite a large 
portion of the refrigeration which is developed where the ice 
and salt do come in direct contact is used in the freezing to- 
gether of the ice which has no salt mixed with it. This is es- 
pecially true at the top of the tank, where there v/ould be very 
little or no brine dripping down through. 

The proper way to charge the tanks of the gravity brine sys- 
tem, therefore, is to thoroughly mix the ice and salt together. In 
a few cases this is done before the ice is filled into the tanks, but a 
better way is to salt the ice as the tanks are being filled. If the 
ice is crushed by a machine and the tanks are filled through a 
spout, this is a comparatively easy matter. Where the ice has 
to be crushed by hand it should be broken as finely as possible 
and no pieces of ice larger than a man's fist allowed to go into the 
tank. This is sometimes difficult to do where the ice is broken 
with a sledge hammer or an axe, but with care big pieces may 
be avoided. It might be stated here that the finer the ice is 
broken the better is the action obtained from the salt; that is, the 
less salt it will take to do a given amount of refrigerating. 

In refilling tanks it is well to first put on a certain amount 
of salt, whatever is required, and then settle the honeycombed 
ice already in the tank by stirring with a stirring stick. After 
the tank is filled a small amount of salt may be placed on top and 
thoroughly stirred into the ice by the use of the stirring stick. 


This stirring stick may be constructed of a piece of ij4 by 3 
inch hard wood with a tapering point at one end, smoothed off 
to a handle at the other end, and made about four to six feet in 

The tanks of the gravity brine system should be cleaned out 
at least once a year, as a certain amount of mud and dirt will ac- 
cumulate at the bottom even with the most careful handling of 
salt and the cleanest possible ice employed. In filling the primary 
tanks of this system the instructions above may be followed 
closely and may be much more readily carried out, as plenty of 
space is available for the stirring of the ice and salt. The best way 
to proceed in filling the primary tanks of the gravity brine sys- 
tem is to detail two men in the tank house, one for salting the 
tank, and the other for stirring the salt into the ice. If only one 
man is available the ice should be handled slowly so he may get 
salt fully stirred into the ice. In this way a very thorough mix- 
ture can be obtained and economy will result. The flexible spout 
which feeds the ice into the primary tank can be arranged so 
that it may be held in any position by the use of a rope. It is not 
necessary that this should be held in the hand. 

The direction and remarks regarding the gravity brine sys- 
tem as above apply equally to any tank system employing ice and 
salt. No exact directions can be given as to quantity of ice and 
salt required for the reason that the conditions are constantly 
changing. It may be remembered as a rule, however, that the 
quantity of ice melted, goods cooled and temperatures produced 
are in almost direct proportion to the amount of salt used in the 
tank. The more salt, the more ice melted, the more refrigeration 
produced, the more goods cooled, or the lower temperature ob- 
tained. Pay no attention whatever to the amount of ice being 
used. It is the salt on which you depend for gauging the opera- 
tion of the house. As a guide it may be said that from five to 
fifteen pails (25 lbs. each) will be used on a primary tank of the 
gravity brine system which has a dimension of about 4x5 feet 
at the top and 10 feet deep, under average conditions. 




It is not expected that this chapter will be of much assist- 
ance to the experienced ice harvester, but those new in the busi- 
ness and persons having a comparatively small amount of ice 
to house may be able to obtain some information in regard to 
the methods used, and select such tools and devices from those 
described as will best suit their particular needs. Natural ice 
has been talked down, legislated against and generally speaking 
has come to be regarded as a back number for cold storage pur- 
poses, but a large percentage of the perishable goods stored in 
the two northern tiers of states and in Canada are still stored 
in structures cooled with natural ice, and the harvesting, handling 
and storing of the natural ice crop is therefore of sufficient im- 
portance to warrant a fair description. In the states which are 
in about the same latitude as New York and Minnesota and 
throughout Canada, a failure of the ice crop is unknown, and 
ice forms quite regularly to a thickness of from fifteen to thirty 
inches. In Pennsylvania and Iowa and the states in the same lati- 
tude and isothermal conditions, ice is usually harvested of a 
thickness ranging from eight to fifteen inches, sometimes thicker. 

Before the introduction of the ice machine, natural ice was 
harvested as far south as Tennessee and Missouri. In some 
isolated cases this is still done, but the crop is uncertain, and as 
the ice is thin it is very expensive to harvest. Probably the thick- 
est ice on record is harvested at Winnipeg, Manitoba, Canada, 
where it reaches a thickness of forty inches, at times even more, 
and almost invariably of excellent quality. The lake ice harvested 
in Minnesota and Wisconsin is almost marvelous in its purity 
and brilliancy. Ice has been cut in these states during three sue- 


cessive winters, eighteen or more inches in thickness, free from 
snow or white ice, and clear and transparent as spring water. 
Lake Superior ice, owing to the beautiful, clear water from which 
it is frozen, is of excellent quality. It is on record that ordinary 
newspaper print has been read through a cake of Lake Superior 
ice twenty-nine inches in thickness. The immense harvests of 
the Kennebec and Penobscot rivers of Maine and the Hudson 
in New York, are of national reputation. Ice from these rivers is 
used largely among the populous coast cities of the East, and be- 
fore the advent of the ice machine, was used extensively in the 
Southern states. The shipment of ice south has now practically 
ceased, and even some of the chief cities of the North Atlantic 
seaboard now use the manufactured article to a large extent, 
because, owing to the Board of Health regulations in many 
places, natural ice can only be used for cooling purposes. 

Ice of a thickness of from ten to sixteen inches handles 
well and cuts up economically if used for retailing by wagon — 
a thickness of fourteen inches being probably the most desirable. 
It is not of course always possible to get the thickness desired 
owing to the exigencies of the weather during harvest. The 
maximum thickness which is formed in the locality where har- 
vested, also necessarily limits in this direction. In southern 
locations it is difficult to get ice thick enough, while further north 
the ice often becomes too thick to handle to best advantage. 
To get a good quality of ice into the house at a low per ton cost 
is the serious problem of the ice harvester during the winter. 
To the end that advantage may be taken of favorable conditions 
of the weather and other related matters, these should be closely 


No accurate figures can be given as to the cost of ice de- 
livered in the ice house, owing to local conditions, which are of 
necessity different in every instance. Ice has been housed in a 
Lake Michigan town in Wisconsin for the seemingly impossible 
cost of six cents per ton. The conditions were ideal for the cut- 
ting of ice, and were as follows: House on lake shore; steam 
hoist, with low fuel cost, for hoisting ice directly from water 
into house ; no snow to contend with ; perfect ice harvesting 


weather with temperature ranging from zero to twenty degrees 
above; ice of a uniform thickness of eighteen to twenty inches; 
labor cost 75 cents per day for experienced men. It may be 
noted that these exceptional conditions are exceedingly rare, 
so that the cost as here given cannot be duplicated except in a 
very few cases, but by taking the above as a basis for calculation, 
it is possible to estimate approximately the cost of harvesting 
under conditions varying from the above. 

Ice cut and handled during fairly favorable weather and 
hauled not more than a mile, may be housed in northern latitudes 
for twenty-five cents per ton, perhaps somewhat less. Further 
south, with ice much thinner and contending perhaps with more 
or less snow, rain, or thawy weather, the cost will be from two to 
four times as much. Should the house be situated at the ice 
field, the cost may be reduced ten to fifteen cents per ton, or 
more, according to the length of haul avoided. It is assumed in 
these estimates that no haul w411 exceed four miles. 

The cost of hauling ice depends -also greatly on whether the 
ice is hauled on runners or wheels, as a much larger load may be 
hauled on runners. A fall of snow sufficient for sleighing is 
therefore a boon to the harvester whose house is located at some 
distance from the field. The snow must of course be removed 
from the field, but this is more than offset by the improved fa- 
cility afforded for transportation. An excessively heavy snow- 
fall, however, may add much to the cost of harvesting, as the 
ice has to be uncovered. Should a heavy rain follow the plow- 
ing and making ready of the field, the rain being perhaps followed 
by sleet and snow, the ice harvester's lot is not a happy one. Not 
only must the work be done over again, but perhaps the recent 
fall of snow must be removed, or the snow ice resulting planed 
off. Other minor items, like loss or breakage of tools, and con- 
tingencies which come up from time to time, influence the ulti- 
mate per ton cost of ice delivered in the house. 


Before undertaking to harvest a supply of ice the harvester 
should inform himself regarding the legal and sanitary regula- 
tions of his locality. He should be fully satisfied that the field 
is lawfully his property, and that all Board of Health and other 


rules are fully complied with. Most of the larger cities and 
many of the smaller ones have quite stringent ordinances regu- 
lating the harvesting and sale of ice. When used for refrigera- 
tion or cooling purposes only and not for family use, ice can 
usually be cut from any source. Some cities, however, will not 
allow ice to be harvested for any purpose whatever from waters 
suspected of pollution by sewage or otherwise. 

The selection in the first place and the care of the field prior 
to harvesting, are both essential for securing a good quality of 
ice, and an economical cut. The prompt removal of snow from 
the surface of the field as fast as it falls constitutes the chief 


labor of preparing the field for harvest. It is seldom that a field 
of ice freezes sufficiently thick to cut without one or more snow- 
falls upon it. Flooding, or "wetting down," the ice, is resorted 
to by some with the first fall of snow, especially in the <;outhern 
tier of natural ice states. When the ice is intended for family 
trade this process should not be resorted to, as all dirt and impuri- 
ties lying on the surface of the ice are frozen on and become im- 
bedded in the ice. 

The "wetting down" process consists simply in flooding 
the surface of the ice, which saturates the snow with water so 
that it may be frozen into ice, protects the under strata of clear 


ice from thawing weather, and serves to increase the thickness 
of the ice rapidly. A snow ice coating is also thought to make 
the cake tougher and less liable to break in cutting and handling. 
The "wetting down" is accomplished by a gang of men armed 
with narrow bladed ice chisels. A starting chisel (Fig. i), or 
ring chisel (Fig. 2) may be used. The men should proceed in a 
row across the field, punching holes at intervals of say six feet, 
and working at a distance apart of from six to twenty-five feet, 
depending on the thickness of the ice and amount of snowfall. 
A small hole only is necessary. "Wetting down" should be done 



on a cold, still day, when it is reasonable to suppose that the wet 
snow will be frozen solid. In comparatively . warm climates, 
where the natural ice crop is precarious, a fall of snow must be 
dealt with promptly by "wetting down" or removing from the 
field. As small a quantity as an inch of dry snow greatly retards 
the freezing, and the surface of the ice should therefore be kept 
free from the protecting snow blanket. 

In northern latitudes flooding is not often resorted to, and 
the snow is removed largely to prevent the formation of snow 
ice in case of a thaw or rain. Should a rain come on with snow 
on the ice, the snow becomes saturated with water, which when 
frozen makes snow ice. Snow ice also results from a thaw when 
snow lies on the surface of the field. It will thus be seen that in 
some localities snow ice is desired and in others it is avoided. 


Snow ice is porous and white, because it contains air in fine cells. 
Its presence lessens the selling value of the ice, but does not in- 
terfere with its refrigerating value. Perfectly clear ice is de- 
sired and readily obtained in the North, but natural ice free 
from snow is seldom seen in the southern tier of ice states. Any 
heavy fall of snow must necessarily be removed before the mark- 
ing out and plowing can be commenced, and a field of ice per- 
fectly free from snow is desirable at all times. An experienced 
ice harvester will know how to proceed under these different 
weather conditions and varying stages of the harvest, and these 
must be taken into consideration at all times if the novice would 
proceed intelligently. 

For the removal of snow from the field, various devices 
arc in use, depending on the magnitude of the work in hand. 


Good progress can be made on a small field by the use of a hand 
scraper or large snow shovel, especially where the snowfall is 
dry and light. This method is also useful where the snow is to 
be removed from ice which will not bear the weight of a horse. 
For general use in harvesting small crops in northern latitudes, 
the home-made scraper illustrated in Fig. 3 will be found of ser- 
vice. It is easily and cheaply made, and can be made of any de- 
sired size to suit the work in hand. An oak plank, two or three 
inches thick and ten to sixteen inches wide may be used, of any 
length up to twelve or fourteen feet. A piece of J^xij4 inch 
iron fastened to the lower edge will improve the efficiency and 
wearing qualities greatly. A small scraper of this kind may be 
fitted with shafts for one horse and the larger ones with a pole 
for two horses. A small one may be constructed to be operated by 


two men. A handle of round iron flattened and screwed to 
plank, as shown, is useful in swinging the scraper into position 
or in lifting over banks at the dump and as a means of holding 
on. If preferred, a rope may be attached in a similar manner 
for this purpose. 

The larger and more durable cleaning-off scrapers which 
are used on larger fields may be purchased from the manufac- 
turers. Fig. 4 illustrates a very good machine for this purpose. 
Fig. 5 is a common form to be purchased at a low cost. Its opera- 
tion is similar to the home-made scraper shown in Fig. 3. Where 
the snow is heavy or deep the scoop scraper illustrated in Fig. 
6 is used. These range from six to eight feet in width, depend- 
ing on the character of the work. After the heaviest snow is 
removed the cleaning off scraper may be put on for removing 
the loosened snow. Should a thick crust form on the snow some 


expedient must be resorted to for loosening it, so that it may 
be scraped; a disc harrow or a modern ice field cultivator will 
sometimes be found useful for this purpose. 


As the snow is scraped from the ice it is generally best to 
remove it to some distance from the place of cutting, either to 
the shore, or far enough from the field to prevent the ice from 
"flooding," either before or after cutting commences. Where 

FIG 6. — Stoop SCRAPER. 

the field is located on a large body of water, the snow is sometimes 
scraped into piles or windrows know as "dumps." The "dumps" 
may be hauled away on sleds or with the scoop scrapers or self 
dumping scrapers, or they may be allowed to remain on the ice. 


If allowed to remain on the ice a deep groove is sometimes plowed 
around the "dump," the weight of the snow causing the ice in 
this place to break loose and sink beneath the level of the cutting 
field. This method is not resorted to except on large fields and 
in case of an exceptionally heavy fall of snow. 

J L 

-< if wrr. fTf f fy j^ 


A careful harvester will observe the thickness of his field 
from the time it will safely bear his weight, and will know from 
day to day the exact thickness he can depend upon, so that when 
the time comes he may act promptly. The thickness is ac- 
curately determined by the use of an ice auger (Fig, 7), and 
measuring iron (Fig. 8). The measuring iron has inch marks 



on it, and is bent up on the end, so that it can be inserted through 
the hole made by the ice auger and drawn up against the under 
side of the ice. The thickness of snow ice, if any, may be noted 
at the top. For more accurate work three holes may be bored, 
forming a triangle, and slanting toward each other at the bot- 
tom ; a small saw is used for cutting the triangular plug by saw- 
ing from hole to hole. 


If sufficient snow ice or dirty ice is present to be a detri- 
ment to the quality of the crop, in the northern latitudes, it is 
generally removed before the ice is housed. This may be done 
by the use of the snow ice planer on the field, or by the elevator 
ice planer as the cakes pass up the incline. Where the endless 



chain elevator is not in use, the snow ice must of course be re- 
moved on the field. The field planer (Fig. 9) is used in con- 
nection with the marker with swing guide. The plane is usually 
set to remove two inches of ice at a time, as a smoother job re- 
sults than where a deeper cut is made. If it is necessary to re- 
move more than this, a second or third grooving and planing 
takes place. The best job of planing may be done by using a 
2 1 -inch guide on the marker and using a check gauge, by which 
the groove is cut to the exact depth of the snow ice to be re- 
moved. Then the plane being twenty-two inches wide, and the 


knife set at the bottom of the guide plates, will lap over one inch 
on the planed portion, removing the marked grooves com- 
pletely, and leaving the surface as smooth as new ice. An im- 
proved ice field cultivator requiring no marking has now largely 
superseded the above method. 

A marker with guide which can be adjusted from twenty- 
two to twenty-one inches is very convenient for use in planing. 
The chips of ice resulting are removed in the same way that a 
heavy fall of snow would be. . The chips being very heavy make 
the planing of snow ice on the field a very expensive operation. 


Where the harvest is of sufficient magnitude to warrant, the use 
of the elevator planer (Fig. lo) is greatly to be desired. This will 
remove any thickness of snow ice, reduce the cakes to the same 
thickness and leave the upper surface of the ice corrugated, which 
will prevent breakage when removing ice from the house. A 
chip conveyor (Fig. ii) removes the ice chips and slush a dis- 
tance from the elevator, and is alnfiost a necessity in conjunction 
with the elevator planer. 


With the field clean, free from snow and of the desired thick- 
ness, the marker is put to work. It is best to start the marking 


plow by stretching a strong line between two stakes driven into 
auger holes in the ice about 200 feet apart, to serve as a guide. 
As all following marks are made from the first, it is important 
that this should be straight. A long plank as a straight e(.\fi;e is 
used to guide the hand plow (Fig. 12) or a line marker (Fig. 
13) may be used as a substitute. Either is followed by the regu- 
lar marker (Fig. 14) with guide which goes over the field, cut- 
ting grooves parallel to the first. The marker is used only for 



the first grooving, the greater part of the cutting being done by 
the deeper field plow (Fig. 15). In marking out the first groove 
the operator should take care to hold the marker upright to pre- 


vent cutting irregular shaped cakes. After the first groove is 
made the guide on the marker runs in this groove, gauging the 
distance of the second. This is repeated over the entire field. 


It is important that the cross marking should be at right 
angles to the first, or parallel marking, for which purpose a large 
wooden square ten or twelve feet long is used. By this method 
it is comparatively easy to have the cakes square. Cakes 22x22 


inches, or 22x32 inches are the common sizes. Marking and 
plowing may be done with one machine, where the ice field is 
small. The swing guide plow (Fig. 16) is the one used for this 
purpose. After the ice is marked out the guide is removed and 


the field plowed over as with the regular field plows. Swing 
guide plows are generally made with seven teeth and either six, 
seven or eight inches in depth. 

A well equipped harvester has several different plows for 
the different purposes. Following the marker a six-inch, nine- 


tooth plow is run in the marker grooves, making these about five 
inches deep. Following immediately behind is another plow, 
eight inches deep, with eight teeth, making the grooves seven 
inches deep. This is deep enough for ten or twelve inch ice, 
but if the ice is fourteen or sixteen inches thick, still another 


plow follows, ten inches deep with six teeth, making the grooves 
about eight or eight and a half inches deep. Should the plows 
be somewhat dull, perhaps this depth is not reached, and a sec- 
ond plowing with the ten-inch plow becomes necessary, probably 
making the grooves nine or ten inches deep, which is sufficient for 
ice sixteen inches thick, or even more. 



The headlines in which the large floats are to be barred off 
are run deeper, some of the large companies having a twelve- 
inch, five-tooth plow for this purpose ; still others deem it economi- 
cal to use a fourteen-inch plow on very thick ice. Where the 
harvest is comparatively small, a number of the plows mentioned 
may be dispensed with, even to doing the total cutting with the 


swing guide plow (Fig. 16). A set of plows commonly used 
by the smaller harvester consists of a marker, an eight-inch, 
eight-tooth plow and a ten-inch plow. If the ice to be cut does 
not exceed twelve inches the ten-inch plow may be dispensed 
with; a marker and a nine-inch seven-tooth plow is used as a 
set also, and is a favorite with the small harvester. 


The plow rope (Fig. 17) by which markers and plows are 
drawn, should be nine or ten feet long. This prevents the front 
end of the plow from rising and causing a "chatter,'' or irregu- 
lar cutting. Many, however, use shorter ropes or none at all. 
The regular plow or grooving harness with whiffle-tree well 
elevated as shown in Fig. 18, is more convenient and easier on 
horses than the ordinary harness. Generally speaking, about 


half or two-thirds of the thickness of the ice should be cut through 
by the plow; but not less than four inches of ice should be left 
between the bottom of the groove and the water below. Four 
inches of solid ice is necessary to safely bear the weight of a 
team of horses. Too much ice should not be plowed in advance 
of the housing capacity ; enough for two or three days is ample ; 
then in the event of a thaw or rain labor is saved, as the grooves 
freeze up very quickly. 




^SHOP£ imt 






No matter how small the harvest of ice, floats of some size 
are used, as they facilitate the floating of the ice to the channel 
where they are separated. A float consists of a number of cakes 
of ice, usually from fifty to one hundred, and if floated some dis- 
tance they are made much larger. The size on large fields is de- 
termined by the deep grooves already referred to as forming 
headlines for floats. The channel to the elevator extends across 
the end of the field. The deep grooves for sawing are located 



about twelve or fifteen cakes apart and run lengthwise of the 
field, while barring-off grooves run in the opposite direction, 
or parallel to the channel and are from four to eight cakes apart. 
By barring off the longest side of the float much sawing is saved. 
Fig. 19 shows a diagram of the layout of an ice field, house, 
channel, etc. The location of the channel for floating the cakes 
to the incline should, of course, be selected before marking out 
and plowing the field. The channel should be plowed with a 

FIG. 20. — TCE SAW. 

deep groove on each side, and the ice removed by sawing out 
with the hand ice saws (Fig. 20). Or, if plows are not plentiful, 
the channel may be sawed out while the field is being plowed. 
The ice from the channel may be sunk under the ice along the 
sides of the channel, as it is usually more or less irregular and 

In sawing out for a channel the cakes should be sawed 
slightly narrower at the top, so that they may be readily sunk 


under the channel sides. Any broken or odd shaped pieces 
which come into the channel should also be sunk in the same 
manner. This disposes of them easily, and as this broken ice 
freezes to the under side of the ice field it aids greatly in sup- 
porting the channel sides, which have a strong tendency to flood 
from the continued weight and travel. Where the field is on a 
river, or where the channel is long, it may be necessary to put 
braces across to prevent the channel from closing. A simple 


device of this kind is shown in Fig. 21. It should extend the 
same distance above and below the ice, and be out of the way of 

FIG. 22.- 

::aulking bar. 

passing cakes. Water sprinkled around the uprights where 
they pass through the ice will soon freeze solid and make a strong 


In breaking out the floats from the planed field, it is best 
to select only a sufficient area for the day's pack. The grooves in 
the field adjoining this area are calked tightly with chips to 


prevent the water running into and freezing in the grooves. 
The calking bar (Fig. 22) is used for this purpose. With the 



ice saws the grooves at the end of the selected area are sawn 
through and a float is broken off by striking into the groove at 



the back, in several places, with the barring-off tool, or breaking 
bar (Fig. 23). The fork bars (Figs. 24 and 25) are likewise 


used for this purpose. The splitting fork (Fig. 26) is also much 
used for barring off thick ice, and is a general favorite for the 
purpose, even on moderately thin ice. 


The floats at the channel are broken up into strips, or small 
floats of single or double rows of cakes, and when these are in 
the channel they are separated into single cakes. For this pur- 
pose the channel chisels (Figs. 2^ and 28) are used. When the 
grooves are much frozen the three tined fork bar (Fig 29) is 
used to good advantage. When the weather is frosty and the 


grooves in good condition the ice will cleave very accurately 
from top to bottom of the grooves; but if the weather be soft 
and the grooves badly frozen, it is often necessary, on thick ice, 
to use the house-axes (Fig. 30) to trim up the cakes. It is only 
possible to do this on a comparatively small harvest where the 
ice is hauled out on a table before loading. This house-axe trim- 


ming is impossible where the endless chain elevator is used. 
When trimming with the house-axe it is best to hew the cakes 
a trifle narrower at the bottom, as the ice will then loosen much 
easier from the house and with less breakage. 

The methods of removing the cakes of ice from the water 
are so numerous that the ice harvester may easily select the one 

FIG. 30. — HOUSE AXE. 

best adapted to his needs. For the handling of a small harvest 
of less than one hundred tons an inexpensive rig must of course 
be selected, but when housing several thousand tons or more 
the most improved endless chain elevators make a great saving 
in the cost per ton. Two men with tongs will pull a small cake 
of ice from the water, but some simple device is generally to be 


preferred even for the filling of a farm ice house of ten to 
twenty-five tons capacity. 

A simple and easily portable rig for raising ice from the 
water and placing it directly on the conveyance is shown in Fig. 


31. It consists of a simple lever or pole, supported on a post set 
in a base or platform. The lever is supported from the top of the 
post by a rope or chain giving play enough so that the cakes may 
be lifted and swung over the sleigh or wagon. The necessary 


leverage for lifting any size of cake may be obtained by adjusting 
the chain at the required point on the pole. A rope attached to 
the long end of the pole enables the operator to secure a lift 
which would otherwise be impossible. Fig. 32 shows a rig fre- 
quently used, especially in some parts of the West. It will raise 



the ice with little effort and deposit it directly on the conveyance, 
but has the disadvantage of not being easily transported, and is 
very slow in action. 

The inclined slide and table (Fig. 33) is the most common 
device in use for removing the cakes from the water and placing 
them in a position to be easily loaded- Two active men with ice 
hooks will pull out on the table a great many cakes per day, 


but quite often a horse is employed, in which case a draw-rope 
is used, that passes through a pulley fixed to a cross-bar above the 
table (see Fig. 34). The jack (Fig. 35) is also used for this 
work. Sometimes the horse or horses pull directly across the 
table without using the pulley; two horses, working both ways 
and using a grapple on both sides of the incline, will haul out a 
surprising number of cakes, enough to keep busy a large number 


of teams. Fig. 36 shows a good arrangement of table on shore 
and a direct pull across the table. Where a table is used, it 
should, to facilitate handling, be slightly higher than the con- 


The endless chain elevator already referred to, may be pur- 
chased from the manufacturers with almost any variation to fit 
individual needs, and is a necessity for the economical housing 


of ice on a large scale. Fig. 37 shows an apparatus of this kind. 
Some of the large companies harvest and place ice in the houses 
at an almost incredible speed with these improved facilities. It 
is on record that 720 tons of ice per hour have been transported 
from the water to the houses by a single apparatus. 


Where ice is hauled from the field to the house, the simplest 
method in use for elevating into house where a very small amount 
is stored, is the inclined slide, up which the ice may be pushed 
by two men with ice hooks. The hoisting crab (Fig. 38) with 
hoisting tongs (Fig. 39), together with the slide, may also be 
used, or the single gig elevator as shown in Fig. 40. In this cut it 
is shown raising ice directly from the water. It is also well 

■\.^i.^uJimi i.m 


adapted to handling ice delivered by conveyance. A double gig 
elevator, operated by means of a hoisting engine, makes a first- 
class rig for moderately large houses, and where the amount of 
ice is sufficiently large, the regular endless chain elevator with 
bars, same as used for removing ice from the water, is largely 
in use. Hoisting tongs (Fig. 39) are in some localities largely 





in use for housing ice, and are used for lifting cakes directly 
from the water to the chute conducting it to the house ; usually 
two pairs of tongs are arranged so that one pair goes down as 
the loaded pair goes up. This is a comparatively slow process, 
but it is a good outfit where small quantities are handled. 

The method of storing ice in the house should be governed 
by the purpose for which it is to be used. If the ice is to be used 
for cooling purposes in the old overhead ice cold storage house, 
and none of it to be removed, it should be packed as closely as 
possible, and the joints between the cakes calked or packed with 


chips, using the calking bar already illustrated in Fig. 22. This 
method is satisfactorily employed where the ice is not to be re- 
moved from the house, but in other cases it is not to be recom- 
mended, as the ice freezes together quickly as soon as the top 
tier begins to melt. When the ice is to be removed from the 
house it is best not to pack it too closely. 

There are several ways of packing, any of which will make 
It possible to remove the ice from the house with very little 
labor or trouble. Where the ice is quite thick the cakes may be 


hewn narrower at the bottom, as already suggested, and the 
cakes stored as closely as they will pack. With thinner ice it is 
best to leave a space of one to three inches on the sides of the 
cakes all around. Care must be taken to have the seams in a 
straight line in each direction. The starting chisel (Fig. 41) 
is useful for this purpose. Should the cakes be of different 
thicknesses, as w-hen harvested from a running stream, they 
should be adzed off to an even thickness, if this work has not al- 
ready been done by the snow ice plane or the elevator planer. 

No matter what method of storing is used, the successive 
tiers of ice should be so placed as to break joints, the object being 


to bind the ice into one solid body and prevent it from caving 
or spreading. If this simple rule is followed, pressure on the 
sides of the house is avoided. Disastrous results have followed 
the careless packing of ice. Ice 22 x 32 inches is very good for 
breaking joints, as one tier may be placed in one direction, and 
the next in the opposite. Where the 22 x 22 inch cakes are stored, 
it is best to harvest some double-sized cakes for binding pur- 
poses. Many harvesters do not break joints oftener than 
every six or eight feet but "every tier broken" is better and safer. 
Where some kind of covering is used, usually the two top tiers 
of ice in the house are packed close together to prevent the 


covering from working down into the seams. In the modern 
houses, where no covering is used, and for cold storage purposes, 
this is unnecessary. 

Some harvesters pack ice largely on edge, placing only 
enough on the flat side to form a binder to prevent the ice from 
moving. The small edging-up tongs (Fig. 42) are much used for 


this method of storing. The main advantage claimed for edge^ 
storing is that for a given space used, ice will loosen much more 
easily from the house and with less waste. One tier on edge and 
one flat makes a good combination for easy loosening. 

For covering ice in the house, shavings, sawdust, straw or 
hay is used. Salt or marsh hay is thought best for the purpose. 


Ice dealers use covering material, but for cold storage uses it 
is not customary. 

It should be borne in mind in every case that where ice is to 
be removed from the house for sale or use, chips made in the 
house during the filling of same should be thrown out and not 
chinked into the ice. Where ice is chinked the chips melt first, 
running down into the seams of the lower tiers, freezing there 



and forming a solid body of ice, difficult to remove without much 
labor and breakage. 

The prevailing idea that thick ice will keep better and longer 
than that which is comparatively thin, is erroneous. Regardless 
of the thickness of the ice, the cakes in the interior of the pile do 
not melt until exposed to the action of the air, the meltage being 
almost wholly on the top, sides and bottom of the mass. When 
ice is put into the house in quite cold weather, it will take the 
temperature of the outside air when exposed during transit to 


the house. If the house is filled with ice at the temperature of 
the air, say at 20° F., the first ice to melt is at the top of the 
house, and the water from the meltage runs down into the joints 
between the cakes of ice lower down in the pile. These being at 
a temperature somewhat below the freezing point of water, the 
meltage from above is frozen into ice, in some cases cementing 
the cakes into a solid mass, as above described. Ice removed 
from the interior of the house in the fall generally shows no 
signs of meltage whatever. 


The following lists are given as a guide to those who are 
unaccustomed to cutting ice. The five lists here given, with the 


size of the harvest for which each is suited, are offered as a basis 

on which the new beginner may form an estimate for his own 

particular conditions. 

Set No. I. — Suitable {pr use in harvesting up to loo tons. 

I ice plow with swing guide. 2 ice hooks. 

I splitting chisel. 2 pairs ice tongs and i 4-foot saw. 

Set No. 2. — Suitable for harvesting 100 to 1,000 tons. 

1 ice plow with swing guide. 
I breaking bar — pad end used as calking chisel. 
I splitting chisel. 
I 4-foot saw. 

I grapple — to raise up incline— or i market tongs if sweep arrange- 
ment is used. 
I plow rope. 

1 line marker. 

2 to 6 ice hooks. 

3 tongs. 

Set No, J. — Suitable for harvesting 1,000 to 2,000 tons of ice, 

using six to ten men and two horses ; hoisting with one grapple. 

I 8-in. swing guide plow. i plow^ rope. *^ 

I breaking bar.* i line marker. ' 

I calking bar.t 2 to 3 doz. 4l/^-it. ice hooks. 

I bar chisel. ^ i to 6 doz. 6- ft. ice hooks. 

1 No. 2 splitting chisel. ',, 1 to 12 doz. 14- ft. ice hooks. 

2 5-foot saws. I i2-in. top gin. 

I grapple and handle. i 12-in. wharf gin. 

Set No. 4. — Adapted for harvesting 2,000 to S,ooo tons of 
ice, using ten to fifteen men and three or four horses; hoisting 
with two grapples. 

I 35^-in. marker, 22-in. Sw. Gd. 
I 9-in. plow (or 8-in.). 
I No. I splitting fork. 
I breaking bar. 

1 calking bar. 

2 bar chisels. 

I No. I splitting chisel. 

3 5-ft. saws. 

2 grapples and handles. 

2 plow ropes. 

I line marker. 

I doz. ^Vi-it. ice hooks. 

I to 6 doz. 6-ft. ice hooks. 

1 to 6 doz. 14-ft. ice hooks. 

2 12-in. top gins. 

2 12-in. wharf gins. 

Set No, 5. — Outfit for harvesting 10,000 to 15,000 tons of 
ice, or more, engaging, say, fifty men and four horses; hoisting 
with incline elevator, and filling three chambers at once. 

I 3^/4-in. marker, 22-in. sw. gd. (ex- 
tra 32-in. guide for 22 x 32-in. 
ice.) (Extra 44-in. guide for 
22 x44-in. or 44-in. sq. ice.) 

I 6-in. 7-tooth plow. 

I 8-in. 7-tooth plow. 

I lo-in. 6-tooth plow. 

1 6-in. hand plow. 

2 No. I splitting forks. 

1 No. I fork bar. 

2 calking bars. 

6 bar chisels. 

1 No. I canal chisel. 

2 No. 2 splitting chisels. 
6 5-ft. saws. 

4 plow ropes. 

I scoop net. 

I auger. 

I measure. 

4 doz. 4^/>-ft. ice hooks. 

I to 4 doz. 8-ft. ice hooks. 

I to 2 doz. i2-ft. ice hooks. 


The quality or number of tools required is largely governed 
by the speed with which it is desired to harvest the crop. The 
sets listed above are for average work ; if fewer men are employed 
the sets may be decreased, and for rapid work increased. It is 
of course desirable to get the ice housed as quickly as possible 
to avoid changes in the weather, snows, etc. Many, however, 
prefer to harvest slowly, with a small crew of men, so as to 
keep their hands at work during the winter, in which case, of 
course, they run the risk of having their ice break up because of 
mild weather before thev have their houses filled. 




By freezing, water expands so tliat eleven volumes of water 
become about twelve volumes of ice. Consequently the specific 
gravity of ice is less than that of water, and ice will f oat on water. 
When water is transformed into ice its temperature is not 
changed, but remains at the "freezing point" so long as it remains 
in contact with water. So also when ice is melting, the tempera- 
ture remains at 32° F. until all the ice is transformed into water. 
By freezing, the latent as well as the sensible heat of the liquid 
is liberated, and when the ice melts a certain amount of heat is 
absorbed, being taken from the surroundings. 

Snow is equal to ice in refrigerating value, and a pound of 
dry snow has the same cooling effect as a pound of dry ice, but 
if the ice or snow contain water, their cooling effect is corres- 
pondingly reduced. If, for instance, one-tenth part of the ice is 
water, there only remains nine-tenths to be melted, and the cool- 
ing effect is reduced correspondingly. Usually, however, ice har- 
vested in a thaw does not contain to exceed 3% of water, and its 
cooling Q&i^ct is nearly equal to that of dry ice. On the other 
hand, "frozen ice" (ice below the freezing point of 32® F.) re- 
quires but one-half the heat required by water to raise it to the 
freezing point.* Even during a hard frost the ice on the surface 
of the water is only at 32° F., and while harvested it is more or 
less submerged in water at 32° F., so that its temperature will 
rarely be much below the freezing point, except when carted for 
long distances in very cold weather. Supposing it is put into the 
ice house at ten degrees below the freezing point, it only takes five 
heat units to bring it to the freezing point, and its cooling value 
is therefore only equal to one-half that of water through the same 
range of temperature. It follows that it is of comparatively 

*So stated by the late Prof N. J. Fjord, of Copenhagen, Denmark. 



small moment whether ice is harvested in a thawing or freezing 
condition. The difference in its value varies only about 5%. 


It is more important, however, that the ice be packed closely 

in the house. A solid block of ice, a foot cube, weighs about 57 

pounds, but a cubic foot of the ice house will hold only of: 

Ice thrown in at random, about 30 to 35 lbs. 

Ice thrown in and knocked to pieces 35 to 40 lbs. 

Ice piled loosely 40 to 45 lbs. 

Ice piled closely and chinked with fine ice 45 to 50 lbs. 

The limits in ordinary practice are usually between 40 and 
50 pounds, a difference of 20%. The same amount will melt in 
the ice house whether the ice is packed loosely or carefully. Sup- 


pose 15 pounds per cubic foot would melt in the summer, there 
would be left only 25 pounds, where there was originally 40 
pounds, but 35 pounds when 50 pounds were stored. The dif- 
ference in the ice left would therefore be 40%. So it is evident 
that it pays to pack the ice well and fill the house to its utmost 
capacity, consistent with ease in removing, cost of the ice, and 
the purpose for which the ice is to be used. 


The common use of ice is comparatively recent, and the mod- 
ern ice house is therefore of recent development. History records 



that the Romans made use of a form of underground cellar or 
pit to preserve snow, which was used for cooling beverages dur- 
ing the heated term. A similar receptacle has been used in many 
places in this country, especially in the South, and may still 
be met with in remote and thinly settled neighborhoods. Figs, i 
and 2 show the outline of the construction adopted in the old 



style, and the construction of the modern ice pit is seen in Figs. 
3 and 4. 


The first commercial ice houses were built below the sur- 
face of the ground, but at present all are constructed above 
ground, for the reason that drainage is more easily secured, and 
the ice is more easily removed from the house. The protection 
afforded by the earth is of comparatively small value when the 
disadvantages of storing below ground are taken into consider- 


ation. Nevertheless, in places where ice forms only one, two or 
three inches in thickness, or where snow is housed to be used for 
cooling purposes, the ice pit has its sphere of usefulness. Mr. J. 
W. Porter, of Virginia, gives the following interesting informa- 


tion, which, among other things, shows that one of our most 

esteemed presidents was a progressive and up-to-date man : 

Pits are dug in the ground, of such size and depth as is desired to 
hold from thirty to fifty loads of ice. The shape is an inverted truncated 
cone. The walls are lined with slabs of wood, split or sawed, or they 
may be walled with brick or stone. My own is 14 feet deep, 18 feet across 
the top and 10 feet across bottom, walled up with stone and then lined 
with boards standing on end. A one-story tool room projecting beyond 
walls two feet is erected; a very common way is to have a half pitch 
shingle roof start from sills laid outside of walls, with door to pitch in 
and take out. After filling, it is* leveled fine and filled with clean straw 
or forest leaves. The ice is rapidly gathered in pieces and shoved in 
from the wagon, with much less labor than cutting, laying and packing, 
which would be impracticable. Sometimes v^hen ice is not produced, 
great .snow balls are rolled and pitched in and trodden. Upon "Issen- 
tiallo," where Jefferson lived and died, within a rifle shot from where I 
write, is" such an ice house, built by Jefferson, which is 54 feet deep and 
is still used for ice or snow.* 

In packing snow in the ice house, it is advisable to have it 
thoroughly wet when it is put in. More cooling material can be 
packed into the same space when the snow is wet all through than 
when dry and frozen, because it may be tramped together and 
packed more nearly solid. It is then possible to get 50 pounds of 
wet snow into each cubic foot of space, 44 pounds of which is 
dry and as durable and good in every respect as 44 pounds of 
solid ice. Many people think that the snow should be frozen, 
but that is a mistake. If it is dry, wet the snow as it is stored 
or wait until it rains. When it is thoroughly w^et it is time to 
harvest and pack it. 

The water is expelled by trampling, and drains off, leaving 
comparatively dry cooling material, which is as effective and 
keeps practically as well as an equal amount of dry ice. One 
active man can pack and trample together 500 to 1,000 cubic feet 
of snow a day, and with this insignificant amount of labor, snow 
may be used to the same advantage as ice. On the other hand, 
of newly fallen, light snow thrown into the ice house and care- 
fully trampled, only 25 to 30 pounds can be packed within a cubic 
foot, and it will keep no longer than wet snow. 

Ice may be put up and protected from the heat of summer 
at very small expense. The simplest method is '"stacking," which 
consists simply of piling up the ice and enclosing it with a fence- 
like structure, leaving space between the ice and the fence for 
a couple of feet of sawdust or other filling material. No roof is 

•From Green's "Fruit Grower." 


put on, but the ice is covered with a goodly quantity of the same 
material that is used for the sides. This method is not practicable 
for a small harvest as the wastage is too great, but where a 
thousand tons or more are put up in this way, the meltage is 
sometimes surprisingly small, perhaps no greater than 20% to 
30%. Some ice dealers fill their houses and put up a certain 
amount in stacks as well, using the stacks first. This method is, 
of course, only possible where ice can be cut of sufficient thick- 
ness to tier up regularly and could not be used where it was 
desired to put up thin ice or snow, as with the ice pit. It is at 
best only a crude makeshift and can not be recommended except 
in case of insufficient capacity or temporary disabling of ice 
house. Sometimes it is desirable to put up ice in this way while 
awaiting the completion of the cold storage house in which it is 
to be used. 

By the smaller users a variety of means are employed. We 
have known farmers who selected sloping ground that would 
have good drainage and then put down some old rails and cov- 
ered them well with straw. On this foundation the blocks of ice 
were placed, and when the weather was freezing they would pour 
water over the ice and thus freeze the entire mass into one huge 
block. This was then well covered with straw and boards and a 
temporary roof put over it. Ice thus packed on the north side of 
the barn by one farmer furnished the family ice for making but- 
ter and ice cream during an entire summer. Ice may be kept 
piled in a heap on a 2-foot thick layer of sawdust or peat, and 
covered with the same material. 


It is a common idea that the insulated walls of an ice house 
should have air spaces, which if "dead'* — that is, all connection 
with the outside air prevented — are supposed to be fully as good 
or even better insulators than the same space filled with sawdust 
or other filling material. This is a mistake. In a vacant space 
between a cold and warm wall, a circulation of the air will always 
take place, conducting the heat from the warm wall to the cold 
one. If such space is closely packed with dry chaff, sawdust, mill 
shavings, or a like material, the circulation, while not entirely 
prevented, is greatly retarded. Of course tight walls effectively 


stop circulation and prevent, to an extent, conduction, and sev- 
eral partitions of paper or boards in the wall are therefore use- 
ful, but the "dead air space" itself is of comparatively small 
account. It is important that the insulating material with which 
the space is filled, should be dry, and however well it is packed, 
there will always be a slight circulation, the air passing down 
along the cold side of the wall, and up on the outer or warm side, 
and unless the outer surfaces of the wall are air tight, moisture 
will find its way in, will be deposited on the cold side of the wall, 
and will gradually saturate the insulating material. In such cases it 
may be advisable, if convenient, to take the insulating material 
out occasionally to be dried before it is replaced, or it may be 
entirely renewed. The moisture which collects in the material 
nearest the inside wall, is generally supposed to pass through the 
woodwork from the ice. It is, however, really due to a circula- 
tion of air, as stated, and which can not be entirely prevented. 
The reader is referred to the chapter on "Insulation" for further 
information and details. 


In filling an ice house care should be taken to have the ice 
piled in such a manner that in melting or shrinking it will not 
press upon the walls. This is easily accomplished by having the 
floor slightly pitched towards the center of the house, then there 
is less danger of ice sliding towards the outer walls. Disastrous 
results have sometimes occurred from this cause. If covering 
material is used on top of the ice it should be inspected frequently 
and any holes found must be filled at once. Bad meltage toward 
the center of the pile may cause a portion of the ice to break away 
and damage the house. 

In refilling an ice house or the ice room of a cold storage 
plant, it is best to cut away any portion of ice remaining in the 
room which has melted in an irregular way, and remove it from 
the house. This applies to the top layer of ice and the sides. Fill 
around the old ice with the new, adzing off so that both are 
level at the top and form a level bed on which to begin refilling. 
Do not attempt to fill up the spaces left from meltage by throwing 
in irregular shaped pieces or fine chips, as they have no sustain- 
ing power and when the weight comes on them will settle and 
may result in a wrecked or badly sprung building. A case is 


in mind where the chips and loose ice were used for filling and 
after the house was filled it was found necessary to remove a 
considerable amount of ice at great expense and stay up the front 
of the building with heavy timbers. This job cost nearly as much 
as the total cost of filling the house with ice. 


Waste of ice in an ice chamber is largely caused by meltage 
from the top, the sides and bottom. Under proper ice house condi- 
tions no serious waste ever takes place inside a pile of ice. The 
melting from the sides, bottom and top is caused by incomplete in- 
sulation. During the summer in some houses in Denmark (The 
experiments on which the following figures are based were made 
in Denmark, and in applying them to this country proper allow- 
ance must be made for difference in climatic conditions; they are 
too high for average conditions in natural ice territories of the 
United States) the waste from the bottom may vary from one foot 
to five feet according to more or less careful insulation. If the ice 
house is provided with an absolutely tight floor, laid on a thick 
layer of dry sawdust, the bottom waste rarely exceeds eight to 
twelve inches during the year. On the other hand, if the ice is 
piled in the house on the bare ground the waste may reach five 
feet. Placed, on a layer of two feet (after being pressed together 
by the weight of ice) of sawdust or peat, the ice heap will not be 
wasted from the bottom to the extent of more than one to one and 
one-half feet. The causes of waste from the top and sides are, 
first, circulation of air ; second, penetration of heat through walls 
and loft. 

Circulation of air is produced by cracks or openings near 
the floor through which cold air escapes, being replaced by warm 
air entering at the top of the house and striking the ice on its 
downward passage. Such circulation is prevented by having the 
walls as tight as possible, especially near the bottom. It is of less 
consequence whether the house is more or less tight at the top, 
if only the cold air can not escape at the bottom. This fact also 
shows the importance of having the door or doors to the ice 
house as high up on the walls as convenient. In a well-built ice 
house but little waste is caused from a circulation of air coming 
into the house from the outside. 


The main source of waste is the penetration of heat through 
the insulated walls. Experiments have shown that in ice boxes 
of the same construction and all exposed alike, the ice melted 
in the following proportions according to the insulating material 
used, chaff (cut-up straw) being considered the standard, and 
the ice melted in the ice box insulated by that material being 
expressed by the figure loo: 

Cotton dried in a warm room 79 

" on a loft 88 

Husk of barley, dried on loft 90 

Husk of wheat, dried on a loft 92 

Husk of oats, dried on a loft 94 

Leaves " " " " 96 

Chaff •' " " '* 100 

Husk of rice " " " " loi 

Wheat straw " " " ** no 

Saw-dust '• ** " " 1 14 

Peat, dry " " '* *' 116 

Saw-dust, green 170 

Peat, moist 260 

Saw-dust, thoroughly wet 260 

Peat '* " 320 

Loam " " 560 

Sand ** " 630 

From this it is evident that the more moisture there is in the 
material the better it conducts the heat, and the poorer it is as 
insulating material. The difference in the value, as non-con- 
ductors, of the materials usually at hand is comparatively small, 
so that material should be used which is most easily procured, 
be it husk of any grain, or chaff, or sawdust. Only see to it that 
it is dry. For the bottom under the ice, however, chaff or leaves, 
or husks should not be used, as these easily ferment, develop 
heat, and rot. Sawdust or mill shavings is usually the best 
available material for the bottom layer. Branches of spruce or 
the like may also be used to advantage. 

The waste from top and sides of the pile of ice depends upon 
the temperature outside and upon the proportion of surface inside 
of the house as compared with the ice capacity. As the result of 
many careful experiments with large and small ice houses, Profes- 
sor Fjord, of Denmark, established a law according to which the 
daily waste in a well built ice house, for every 100 square feet of 
inside surface is 1.7 pounds for each degree Centigrade of average 
heat. Thus in a house of 1,000 square feet inside surface, in 



thirty days of an average temperature of 15° C. (59° F.) the 
waste would be 1.7 pounds x 15 x 30 x 10, equals 7,650 pounds. 

If there is 45 pounds of ice to the cubic foot, the waste would 
be 170 cubic feet, and if there is only 35 pounds to the cubic 
foot, the waste would be 220 cubic feet. In Denmark, the yearly 
waste would be about 45 pounds for every square foot of the 
inside surface, or if there is 45 pounds to the cubic foot, i^ cubic 
feet ; and with only 35 pounds to the cubic foot, i 2/^ cubic feet. 

If the house is filled with ice to its fullest capacity, the bal- 
ance of ice left, i. e., the house full, less the yearly waste, which 
represents the ice that can be taken from the house during the 
year (it makes very little difference whether much or little is 
taken first or last, provided some is to be kept the year around, 
for whether there is much or little left in the house, the amount 
melted in a day is practically the same) varies according to the 
size of the house, and it may be calculated from the following 
table, the headings of the last three columns representing the 
amount of ice packed in each cubic foot of the house : 

Inside of Ice House. 

Balance Left in a Well-Built 
Ice House, Cu. Ft. 



Sq. Ft. 

Volume i, 
Cu.Ft. 1 

45 lbs. 

40 lbs. 

35 lbs. 


10 X 10x10 


1000 1 





12 X 12X10 


1440 I 







2028 1 







2700 1 





18x18x12 1 I512 

3888 i 





20 X 20 X 12 1 1760 

4800 ll 





25x20x12 1 2080 

6000 ' 





30 X 25 X 12 1 2820 

9000 ll 

12000 ' 





40 X 25 X 12 






50 X 25 X 12 


18000 ' 





60 X 25 X 12 






80 X 25 X 12 


24000 ll 




In this table the waste from the bottom is calculated at one 
foot. If the bottom is poorly insulated, more waste should be 
calculated, as mentioned before. Supposing the bottom waste to 
be two feet instead of one foot, an additional waste of 873% of 
the ice harvested must be expected in a pile twelve feet high. 

By means of these figures it is possible to calculate the size 
of an ice house needed for any purpose in which the amount of 


ice required is known. In the United States a waste of more 
than 20% is considered excessive, and in the larger houses from 
10% to 15% is commonly figured. Professor Fjord's figures here 
given represent too great a wastage, but as they are the only 
known data obtainable they are used as a basis and are given for 
what they are worth. 


For a good simple plan for a farm ice house, that given below 
has been designed by the author. It will be found cheap to con- 
struct and thoroughly practical. The advantages of a supply of 
ice on the farm which will last through the summer are well 
understood by those who are provided with an ice house. Those 
who have never put up ice should arrange to do so during tlie 
next harvesting season. 

Once tried, and the advantages of a supply of ice in hot 
weather experienced, it will become a permanent rule to house 
ice every winter. A systematic course can then be followed, and 
the use of labor-saving tools and methods which expedite the 
work employed. While securing the ice is the chief considera- 
tion, no one should be content with anything short of the best 
methods obtainable ; this is a necessity during mild winters, when 
the crop must be secured speedily or not at all. 

The ice house as here illustrated in Fig. 5, by plan and sec- 
tion, is twelve feet square outside and eleven feet high. After 
allowing for a foot of sawdust or other filling material at top. 
bottom and sides, about eighteen tons of ice can be stored in it. 
If the house is to be built on a sand or gravel soil where drain- 
age is good, no precaution need be taken in regard to the drain- 
age. If, on the other hand, the house is built on a clay soil, 
it would be advisable to excavate a few inches and fill with coarse 
gravel or pounded stone, and if necessary, a porous drain tile 
may be laid through the center of the house and carried to a 
low place outside for conducting away the meltage from the ice. 

The sills consist of double 2 x 4's on which are erected 2 x 
4 studding, 24-inch centers. These are topped with a double 
plate of two 2 X 4's on which rest 2x6 joists, 24-inch centers. 
The studs <ire boarded up outside with novelty or drop siding. 
There is no inside boarding, the sawdust being allowed to fill the 



jlCE fftTJoMsl 

1 ' ■ » I 

^AWPU3T ^^rwJm ^ 





^IcE Door 





ICC (6Tbns 

'mltsf or Prop 2iJti 


■ ■ — 



space between the studs. The roof is constructed of 2 x 4 
rafters, 16-inch centers, boarded and covered with shingles. In 
each gable is a louvre or slat ventilator for the purpose of allow- 
ing free circulation of air. One of these may be made remov- 
able or hung on hinges to allow access for covering the ice with 
packing material. The ice door should be built in two or more 
sections hinged to open outwardly. 

On the inside, pieces of 2-inch plank are placed to keep the 
sawdust or other filling material away from the outer doors. As 
the ice is removed from the house the pieces of plank are removed 
as necessary. The actual material for constructing this ice house 
will cost, under average conditions, from $30 to $40, and after 
figuring labor, the entire cost of the house should not exceed $50. 

This plan is subject to modification as to size and construc- 
tion. By using 2 x 8's or 2 x 6's for studs a larger house may 
be constructed with the plan otherwise unchanged. If the joists 
above ice are objectionable, they may be omitted by using heavier 
studs and rafters, in which case the ice door is extended up into 
gable, making top sections of door in the form of a slat ventilator. 


If ice-cutting tools are not available, it is no reason why you 
should be discouraged. With two or three cross-cut saws, an axe 
or a pointed bar, two or three ice hooks and a pair of tongs, the 
house can be filled. If it is desired to secure a more extended kit 
of tools for next season, it would be well for several farmers to 
combine and exchange work in filling their ice houses. (See 
chapter on '^Harvesting, Handling and Storing Ice'* for further 

The standard size of an ice cake is 22 by 22 inches or 22 by 
32 inches. From 40 to 50 cubic feet of ice-house measure will 
represent a ton. If the ice is packed solid, 40 feet is correct, 
whereas if it is packed an inch or two apart, as some prefer, 50 
feet IS about right. 

When filling ice into the house about a foot of sawdust, 
chopped straw or mill shavings should be placed under the first 
tier of cakes. 

Leave at least a foot of space inside the studding all around, 
which should be filled with packing material as the ice is put in, 


and it is also advisable to fill on top of the ice with a foot or more 
of sawdust or up to the top of the joists. It is advisable to cut 
the cakes of ice as regular in shape as possible, oblong rather 
than square. In this way each alternate tier can be reversed so 
that the joints will be broken, as shown in section. This will bind 
the ice together and prevent it from sliding or breaking apart. 

As the ice is removed from the house, see that the remain- 
ing ice is kept covered with sawdust, and if any holes appear, 
fill them at once. If dry sawdust is not available, straw, marsh 
grass or mill shavings or tanbark may be used. Whatever is 
used should be tramped down solidly. 

Ice houses are sometimes built with double walls, with a 
space of one to two feet wide between, firmly filled with dry 
sawdust or other similar material. It is cheaper and serves the 
purpose well to pile the ice without a floor directly on the ground, 
on a thick layer of sawdust or brush wood. Good drainage must 
be provided, though sometimes in a porous soil no direct outlet 
for water is needed. The outside wall should rest on a stone 
foundation built up slightly above the ground, on the top of which 
the wall may be built of studding and matched boards, the inside 
wall should also be made of matched boards, the space 
between being filled with closely packed insulating material. On 
the beams a loft floor should be laid of loosely packed boards, 
which may be removed while the house is being filled with ice. 
On .the loft floor a layer of insulating material should also be 
laid. The entrance should be placed near the top of the wall 
and be provided with double doors which may be furnished with 
windows to allow light to enter. 

It often occurs that an ice house may be placed inside of 
another building, for instance in the corner of a barn. Instances 
are known where ice has been successfully kept in a hay mow or 
under a straw stack, by providing an opening with double doors. 
Where a room is built within a building, it is best to construct 
the sides, floor and ceiling double, with some non-conducting 
filling material between. The walls should be at least one and 
one-half feet thick, and the ice inside of the room protected by 
a foot or two of marsh hay or clean straw. This is to be kept in 
place as the ice is removed. In building inside of a structure 
used for other purposes provision should be made for draining 


away the drip from the melting ice, so that this may not serve 
to rot the timbers or injure the foundation of the building. 

The following is a description of a house which has given 
good service to its owner: The ground was tiled thoroughly 
for drainage and a shallow surface gutter made all around the 
outside. The foundation was hollow, square building tiles, 
lo X lo X 36 inches, being used. The sills, 2x8, were doubled 
and lapped and well bound at the corners. The 2x6 studs were 
toe-nailed to the sills, so that the sills projected two inches over 
studs on the outside ; girths, 2x4, were spiked two and one-half 
feet apart horizontally and flatwise on the studs, so as to be flush 
with plates and sills. The weather boards were put up and down 
and battened. The lining of i x 12-inch boards was nailed hori- 
zontally on the studs so an 8-inch air space was left, and one 
inch of said space left open at the top for the escape of warm 
air. (The author believes that if this 8- inch air space was filled 
with a good insulating material like dry sawdust or mill shavings 
better protection would be afforded.) For free circulation and 
to accelerate the escape of hot air a ventilator was placed in 
the middle of the ridge of the roof and an opening left in each 
gable end close under the roof. The door extended from three 
feet above the ground level to the level of the eaves, and was 
placed on the up-hill side of the ice house. There was a small 
'door in the gable to receive the last two layers. 

The following description is of an ice house intended for a 
somewhat larger harvest than the preceding and the building is 
more thoroughly constructed. It also presents a better appear- 
ance architecturally. The foundations and floors are of cobble 
stones to provide drainage. The course of cobble stones should 
be a foot or eighteen inches thick, and project slightly above the 
surface of the ground. The sills are double 2-inch stuflF ten or 
twelve inches in width ; the studding of 2 x 10 or 2 x 12 set 24- 
inch centers; the rafters or roof joists to be of sufficient strength, 
depending on the size of the building and kind of material em- 
ployed. Floor joists of 2 x 8, or 3 x 8 may be used, or a floor may 
be laid dow-n loosely on the sawdust which is filled in over the 
cobble stones to a depth of a foot or more. If floor joists are 
used the floor should be of 2-inch stuff, laid open at joints to 
allow meltage to drain readily. The studs are boarded with 


matched lumber outside and inside, and the space between filled 
with insulating material, preferably of sawdust (perfectly dry) 
or mill shavings, well rammed down. The rafters should like- 
wise be boarded underneath and filled, or ceiling joists may be run 
across at the top of the studs forming a floor and an attic. This 
space should be suitably ventilated by slat ventilators in the gable 
ends over attic floor. If an attic floor is put in, the rafters need 
not be filled, the attic floor being filled instead. The general de- 
scription of a model creamery ice house a little further on may be 
consulted in connection with the above. It is not necessary to 
place hay or straw on the ice where all the surfaces in the build- 
ing are insulated as above described, and the room may be filled 
full to the ceiling or within a few inches of same. A little experi- 
ence will show whether or not a covering of any kind is necessary 
or advisable. 

The above methods of constructing ice houses, with one 
exception, are not minutely described with drawings because of 
their simplicity and because individual ideas and judgment can 
best modify them to suit local conditions. The information given 
will enable any experienced carpenter, or even a person ordi- 
narily familiar with tools, to take the material at hand, and erect 
a structure of suitable size and character to meet the conditions. 
The houses already described are not well adapted for ice houses 
intended to hold more than loo to 150 tons of ice. For largef 
houses one of the designs described further on is more suitable. 
In any case the amount of money which can be profitably 
expended on an ice house depends largely on the cost of deliv- 
ering ice to the house. If it costs but twenty cents per ton to 
store the ice in the house, it is not advisable to spend much monev 
in building a house to preserve same ; it would be better business 
policy to build a cheap house, making it larger to allow for 
greater meltage. On the other hand, if the ice in the house costs 
from seventy-five cents to a dollar per ton, it would pay well to 
build in a first class manner after the best plans obtainable. 
Between these two extremes are all the variations which may be 
met by considering cost of ice and cost of construction. These 
remarks apply equally well to ice houses of any capacity. The 
greater the cost of the ice the more money can be profitably ex- 
pended in protecting same from meltage when housed. 



Although a similar construction may not be advisable or 
practicable in this country, on account of the expense, yet 




a description of the Danish methods herewith given, may be of 
interest. The designs shown have been particularly recommended 
for creamerv use.* 

•Abstracted from J. H. Monrad's Dairy Mcsseuger. 



The illustrations taken from Bernhard Boggild's Maeikeribniget repre- 
sent an ice house as usually built for creameries or dairies in Denmark. 




The larger one, (Figs. 6 and 7) will hold 15,000 cubic feet of ice, and 
is built in connection with the creamery. Fig. 7 is a section through 
A-B of Fig. 6. The inside lining is of matched and varnished boards 
placed vertically, on the outside walls, but horizontally on the partition 
and ceiling. D represents the drainage; M is doors for putting in ice; 
L, doors for renewing the saw-dust; V, window; T represents peat or 
sawdust on the floor; H, chaff, husk, sawdust, or other insulating 
material in the hollow walls. All doors are made as tight-fitting as 
possible by tacking cloth on the edges. A, small hall, K connects the 
ice house with the creamery, the ice being thrown out through the flue, 
t, through the upper door, later through the lower ones. 

The small ice house, Figs. 8, 9 and 10, will hold 1,650 cubic feet